JP2002203141A - Method and device for management of bidding price - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve auction environment where it is hard to make an inten tional running-in bid in an Internet auction or the like. SOLUTION: If the bidding time is two days before the bidding term (YES in SA2 and NO in SA3), the bid unit A which is the lowest added price to the highest value at that point of time is set to the double of the specified former bid unit N (SA4). Further, when the bidding time is one day before the bidding term (YES in SA2 and SA3), the bid unit A at that point of time is set to three times of the specified bid unit N (SA5). The bid immediately before the bidding term is made disadvantageous to reduce to half the advantage by the intentional running-in bid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bid price management method and a bid price management apparatus for managing a bid price when operating an auction participating through a communication line such as the Internet.

[0002]

2. Description of the Related Art In recent years, with the spread of the Internet,
Various auctions are held at site b, and an environment is realized in which anyone can participate while staying at home by connecting a personal computer or the like to a predetermined Web site.

[0003] In such an auction, an auction period (bid period) is determined for each product or the like that is exhibited. In bidding, the highest bid at that time is determined in a determined bidding unit (minimum additional price). Many systems charge higher than the price. Also, some auction organizers may notify participants of high price updates (e-mailed when other bidders bid higher than the bid price of the participant) or the highest bidder (low In the auction where the winning bid is set, a notification service such as e-mail will be sent when the participant becomes the highest bidder 24 hours before the end) or if the high price is updated within the bid deadline of 5 minutes Some companies provide various services such as an extension service that extends the time limit of 5 minutes.

[0004]

However, in the above-mentioned auction, at the end of the bidding period, a bid is added by adding only the minimum price to the highest price at that time, and a bid is made. There is a bidding method of manipulating a rise in a winning bid (hereinafter, referred to as “intentional rush bid”). This is not possible with a traditional auction where all participants participate simultaneously,
This is a problem unique to the Internet auction,
Even with the notification service described above, if other participants intentionally bid before the deadline, they will not be notified in time, and even if there is an extension service, they will monitor the bid status of other participants at the bid deadline. I couldn't understand without it.

[0005] For this reason, the presence of intentional last-minute bidding reduces opportunities for other participants to re-bid, and is not fair, which hinders fair price formation. The problem was how to eliminate the last-minute bid.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and has as its object to provide a bid price management method and a bid price management device which can realize an auction environment in which intentional second-run bidding is difficult. And

[0007]

According to a first aspect of the present invention, there is provided a bid price management method for managing a bid price when operating an auction participating through a communication line. After the remainder of the bidding period reaches the predetermined period, the minimum price range that can be added or subtracted from the immediately preceding mid-price, that is, the minimum price that can be added to the highest price just before bidding in a normal auction, or the so-called reverse auction The minimum price range that can be deducted from the lowest price immediately before bidding has been increased from before.

[0008] According to this method, the advantage of the intentional last-minute bidding performed immediately before the bidding deadline can be halved by making the bidding just before the bidding deadline disadvantageous.

In the invention of claim 2, the minimum price range is gradually increased after the remaining of the bidding period reaches a predetermined period.

[0010] According to such a method, the advantage of intentional rush bidding performed immediately before the bidding deadline can be further reduced.

Further, in the invention according to claim 3, the minimum price range is set to be greater than before even after a predetermined period has elapsed since the highest price was bid.

According to this method, it is possible to further reduce the advantage of intentional rush bidding performed immediately before the bidding deadline.

Further, in the invention according to claim 4, the minimum price range to be applied to the first bidding immediately after a predetermined period has elapsed since the immediately preceding mid-price was bidding,
Increased than before.

[0014] According to this method, it is possible to further reduce the advantage of intentional last-minute bidding performed immediately before the bidding deadline.

[0015] The invention according to claim 5 is a method for managing a bid price when operating an auction that participates through a communication line, wherein the bid price is bid after a predetermined period has elapsed since the intermediate price was bid. The minimum price range that can be added or subtracted from the immediately preceding intermediate price has been increased from before.

According to this method, since the bidding after the intermediate price is continuously maintained becomes disadvantageous, it is possible to reduce the advantage of intentional rush bidding performed immediately before the bidding deadline.

According to a sixth aspect of the present invention, there is provided a method for managing a bidding price in the operation of an auction participating via a communication line, wherein a predetermined period has elapsed since the last halfway price was bid. The minimum price range that can be added to or subtracted from the immediately preceding halfway price, which is applied to the immediately following first bid, has been increased from before.

According to this method, since the bidding immediately after the intermediate price is continuously maintained becomes disadvantageous, it is possible to reduce the advantage of intentional rush bidding performed immediately before the bidding deadline.

According to a seventh aspect of the present invention, there is provided a bid price management device which is used for managing an auction participating through a communication line and manages a bid price.
Storage means for storing expiration date information regarding the bidding expiration date, operation means for calculating the remaining period until the bidding expiration date based on the expiration date information stored in this storage means, and with the operation result of this operation means being a predetermined period, Setting means for setting the minimum price range that can be added or subtracted from the immediately preceding intermediate price to a larger price range than before is provided.

In such a configuration, only immediately before the bidding deadline, the intermediate price immediately before, that is, the minimum price that can be added to the highest price immediately before bidding in a normal auction,
The range of the minimum price that can be deducted from the lowest price immediately before bidding in a so-called reverse auction increases. Therefore, by placing a penalty on the bid just before the deadline,
The advantage of a deliberate rush bid immediately before the bid deadline can be halved.

Further, according to the invention of claim 8, there is provided a device for managing bid prices, which is used for operation of an auction participating via a communication line, and a storage means for storing deadline information relating to a bid deadline. Acquiring means for acquiring an elapsed period after the mid-price is bid, and a minimum price width that can be added to or subtracted from the immediately preceding intermediate price when the elapsed period acquired by the acquiring means reaches a predetermined period. And setting means for setting a larger price range than before.

In this configuration, after a predetermined period has elapsed since the mid-price was bid, the minimum price range that can be added to or subtracted from the immediately preceding mid-price increases more than before. Therefore, since the bid after the intermediate price is continuously maintained becomes disadvantageous, it is possible to reduce the advantage of the intentional rush bidding performed immediately before the bidding deadline.

According to a ninth aspect of the present invention, there is provided an apparatus used for managing an auction participating through a communication line and managing a bid price, wherein the storage means stores expiration date information on a bidding expiration date. Acquiring means for acquiring the elapsed time since the mid-price was bid, and applying to the first bidding immediately after the elapsed time acquired by the acquiring means has reached a predetermined period, adding to the immediately preceding mid-price or Setting means for setting the minimum price range that can be subtracted to a larger price range than before is provided.

In this configuration, the minimum price range that can be added to or subtracted from the immediately preceding intermediate price, which is applied to the first bidding immediately after a predetermined period has elapsed since the immediately preceding intermediate price was bid, To increase more. Therefore, only the bid immediately after the intermediate price is continuously maintained becomes disadvantageous, and the advantage of the intentional rush bid immediately before the bid deadline can be reduced.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a configuration diagram showing the entire network auction system according to the present invention. This system includes an auction server 1 owned by an auction organizer who operates an auction site on the Web, an exhibitor terminal 3 connected to the auction server 1 via the Internet 2, and a bidder terminal 4.
・ It is composed of The seller terminal 3
The client terminal for the seller on the site to send information of the product information such as the content and price of the product to be sold to the auction server 1, and the bidder terminal 4 is a bidding participant who participates in the auction. , A client terminal for sending desired products and bid prices to the auction server 1. Note that the exhibitor terminal 3 and the bidder terminal 4 are personal computers that include a communication device such as a modem that enables connection to the Internet 2 via a telephone line and have a Web browsing function. When a seller participates in a bid for a product of another seller, the seller terminal 3 and the bidder terminal 4 are configured by the same personal computer.

The auction server 1 is a bid price management device of the present invention, and as shown in FIG.
Input means 12 and output means 1 connected to CPU 11
3, a RAM 14, a storage unit 15, a communication unit 16, and a clock unit 17. The input means 12 is a device such as a keyboard or a mouse, and the output means 13 is a display device such as a CRT or an LCD, a printer, or the like.
Used to manage and maintain the system. Communication means 16
Is a communication interface for transmitting and receiving a large amount of data to and from the Internet 2, and is connected to the Internet 2 via a public line such as a telephone line or a dedicated communication line. The clock means 17 comprises a clock device having a calendar function, and supplies the CPU 11 with current date and time data.

The storage means 15 comprises various storage devices such as a hard disk capable of storing a large amount of data. The control program of the auction server 1 is stored in the storage means 15, and the CP
The operation of the auction site by the auction server 1 becomes possible by the U11 operating based on the control program and controlling the above components. Also, CPU
11 uses the RAM 14 as a working memory, and performs various data processing based on data described later stored in the storage means 15 and date and time data sent from the clock means 17. It functions as a calculation unit, a setting unit, and an acquisition unit. The storage means 15 stores, together with the control program, the basic bid data file 15a shown in FIG.
5b is stored.

The basic bid data file 15a shown in FIG. 3 (a) contains basic items set at the time of selling for each product requested by the seller via the seller terminal 3, that is, the product number and the corresponding item. Data 101 to 1 of the bidding deadline to be performed, the starting price at the beginning of bidding, and the bidding unit
04. The bid expiration date data includes a bid expiration date (including time) automatically calculated in accordance with a bidding period set by the exhibitor at the time of applying for exhibition of the product. The bidding unit data 104 is the minimum price that can be added when a bidding participant makes a bid, and is also a unit of the bidding price. Price.

The bid management file 15 shown in FIG.
b denotes data used for management during the bidding period, that is, the product number, the corresponding maximum price, the bidding date and time of the highest price (final bidding date), and data 101 and 10 of the management bidding unit.
5 to 107. Highest value data 10
Reference numeral 5 denotes data of the mid-price during the bidding period and data of the contract price at the end of the entering period, which is sequentially updated together with the bidding date / time data 106. The management bid unit data 107 includes
Bid unit data 104 of the basic bid data file 15a
Is stored as the initial data.

Next, the network having the above configuration
The bid price management operation performed by the CPU 11 of the auction server 1 during the auction in the auction system will be described with reference to the flowchart of FIG.

That is, after a bid is started for a certain product, if there is a bid from any of the bidder terminals 4 (YES in step SA1), the time is determined by the bid deadline stored in the basic bid data file 15a. It is determined whether it is within two days (step SA2). Here, if it is not within two days, it is continuously determined whether or not the bid price is equal to or higher than the price obtained by adding the management bid unit (A) stored in the bid management file 15b to the highest price at that time ( Step SA6). The management bid unit (A) at the beginning of the bidding is the same as the bid unit stored in the basic bid data file 15a. If the bid price satisfies the above condition, the bid price is registered as valid. That is, the highest price data 105 of the bid management file 15b is updated (step SA7). If the determination result in step SA6 is NO and the bid price is less than the price obtained by adding the management bid unit (A) to the highest price at that time, the bid price is invalidated (step SA8). Maintain the highest value of

If the result of the determination in step SA2 is YES and the time when the bid is made is within two days of the bid deadline, it is further determined whether the time is within one day of the bid deadline. Is determined (step SA3).
Here, when it was not within 1 day, that is, 2
If it is the day before, the management bid unit (A) is set to twice the bid unit (N) (step SA4), and the process proceeds to step SA6 described above. If it is within one day, that is, one day before the bidding deadline, the management bidding unit (A) is set to triple the bidding unit (N) (step SA5), and then the above-described step SA6 is performed. move on.
Then, the above operation is continued until the bidding deadline.

Although not shown in the flowchart, in the auction server 1, when the bidding deadline is two days and when the bidding date is one day, the highest price at that time is separately displayed on the Web. At the same time, the management bidding unit (A) is displayed as the bidding unit (minimum additional price) at that time.

Thus, during the bidding period, the bidding price is managed as follows. For example, a product has a starting price of 1,000 yen, a bid unit of 100 yen,
Considering a case where a bid is registered (exhibited) in a bidding period of 10 days, the bidding participant, as in the past, can make a bid for
During the day, a bid can be set by setting the price at a high price of 100 yen in bid units until the eighth day. On the other hand, if the bidding unit is set to 200 yen on the ninth day and the highest bid price until then is 1,800 yen, then on the ninth day, it is 1,800 yen + 200 yen, and 2,000 yen is effective. Bid price. Further, when the tenth day (the last day) starts, the bid unit is set at 300 yen, and if the highest bid price until then is 2,000 yen, it becomes 2,000 yen + 300 yen on the tenth day. , 2,300 yen is an effective bid price.

Therefore, by informing the bidding participant of the above bidding system in advance, the maximum price is updated, the maximum value is maintained for a certain period of time, and the maximum value is almost determined on the 10th day (bidding). The advantage of not taking part in the bidding until the expiration date) and deliberately adding only the bid unit of 100 yen immediately before the end to the highest price at that time to acquire the right to win the bid, that is, the advantage of manipulating the increase of the contract price Will be halved. Therefore, intentional rush bidding can be eliminated as much as possible. As a result, it is possible to realize an auction environment in which bid participants can maintain fair price formation without causing unfairness.

In this embodiment, the bidding unit is increased from two days before the bidding period and the bidding unit is further increased one day before the bidding period. That is, the bidding unit is gradually increased during a certain period immediately before the bidding period. Although the case of increasing is shown, the bid unit in a certain period immediately before the bidding deadline may be set to be higher by one time than the previous amount. Even in that case, intentional rush bidding can be eliminated as much as possible.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described. In the present embodiment, a control program relating to the following operation is stored in the storage unit 15 of the auction server 1 described above.

Hereinafter, in the present embodiment, the CPU
The other bid price management operations executed by 11 will be described with reference to the flowchart of FIG.

That is, after a bid is started for a certain product, if there is a bid from any of the bidder terminals 4 (YES in step SB1), that point is the last bid date stored in the bid management file 15b. That is, it is determined whether two or more days have passed since the date and time when the highest value at that time was registered (step SB2). Here, when two days or more have not passed, it is continuously determined whether or not the bid price is equal to or higher than the price obtained by adding the management bid unit (A) stored in the bid management file 15b to the highest price at that time. A determination is made (step SB6). The management bid unit (A) at the beginning of the bidding is the same as the bid unit stored in the basic bid data file 15a. If the bid price satisfies the above condition, the bid price is registered as valid. That is, the highest price data 105 of the bid management file 15b is updated (Step S
B7), and further updates the high price update date / time data 106 (step SB8). When the determination result of step SB6 is NO and the bid price is less than the price obtained by adding the bid unit (N) to the highest value at that time, the bid price is invalidated (step SB9), Maintain the highest value.

If the result of the determination at step SB2 is YES, and the bidding time is at least two days after the final bidding date, it is further determined whether three or more days have passed since the last bidding date. Is determined (step S
B3). Here, when three days or more have not passed, that is, when two days have passed since the last bidding date, the management bid unit (A) is changed to two of the bid units (N) stored in the bid management file 15b. Set in advance (Step SB
4) When three days or more have elapsed, the bid unit (N) is set to triple (step SB5), and the process proceeds to step SB6 described above. Then, the above operation is continued until the bidding deadline.

Although not shown in the flowchart, in the auction server 1, when two days and three days have passed since the final bidding date, W
On the eb, the management bid unit (A) is displayed as the current bid unit (the lowest added price) together with the highest price at that time.

Thus, during the bidding period, the bidding price is managed as follows. For example, a product has a starting price of 1,000 yen, a bid unit of 100 yen,
Considering a case where a bid is registered (exhibited) in a bidding period of 10 days, the bidding participant, as in the past, can make a bid for
During the day, a bid can be set by setting the price at a high price of 100 yen in bid units until the eighth day. On the other hand, after one bidder bids the highest price of 1,800 yen at a certain time, if there is no other valid bid for two days, the bid unit is increased to 200 yen at that time, Thereafter, 2,000 yen, which is the highest value of 1,800 + 200, is an effective bid price. Furthermore, if there is no other valid bid for one day (three days for convenience), the minimum bid unit is further increased to 300 yen at that point, and the maximum bid price until then is 2,
If the price is 2,000 yen, the effective bid price is 2,000 yen + 300 from the fourth day, which is 2,300 yen.

Therefore, also in the present embodiment, the advantage of intentionally performing a rush bid can be reduced by half, and a rush bid intentionally can be eliminated as much as possible. As a result, it is possible to realize an auction environment in which bid participants can maintain fair price formation without causing unfairness.

In the present embodiment, the bid unit is increased from two days after the last bidding date, and the bid unit is further increased after three days, that is, a certain period after the maximum value is updated. Although the case where the bid unit is gradually increased after elapse is shown, after a certain period elapses after the maximum value is updated, the subsequent bid unit may be set once higher than the previous amount. Good. Even in that case, intentional rush bidding can be eliminated as much as possible.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
An embodiment will be described. In the present embodiment, a control program relating to the following operation is stored in the storage unit 15 of the auction server 1 described above.

Hereinafter, in the present embodiment, the CPU
Another bid price management operation performed by the client 11 will be described with reference to the flowchart of FIG.

That is, after a bid is started for a certain product, if there is a bid from any of the bidder terminals 4 (YES in step SC1), that point is the last bid date stored in the bid management file 15b. That is, it is determined whether two or more days have passed since the date and time when the highest value at that time was registered (step SC2). Here, when two days or more have not passed, it is continuously determined whether or not the bid price is equal to or higher than the price obtained by adding the management bid unit (A) stored in the bid management file 15b to the highest price at that time. It is determined (step SC4). The management bid unit (A) at the beginning of the bidding is the same as the bid unit (N) stored in the basic bid data file 15a. If the bid price satisfies the above condition, the bid price is registered as valid. That is, the highest price data 105 of the bid management file 15b is updated (Step S
C5) After updating the high price update date / time data 106 (step SC6), the bid unit (N) is reset as the management bid unit (A).

If the result of the determination in step SC2 is YES and the time of bidding is two or more days after the last bidding date, the management bidding unit (A) is replaced with the bidding unit (N). After setting twice (step SC
3) Perform the above-described processing after step SC4. Thereafter, when the bid price is valid, the step S
While the processing of C5 to SC7 is performed, step SC
At 7, the management bid unit (A) is returned to the bid unit (N), and when the bid price is invalid, the state of the management bid unit (A) being twice the bid unit (N) is maintained.
Then, the above operation is continued until the bidding deadline.

Although not shown in the flowchart, the auction server 1 waits two days after the last bidding date and waits until there is a next valid bid.
On the eb, the management bid unit (A) is separately displayed together with the highest price at that time as the bid unit (lowest additional price) at that time.

Thus, during the bidding period, at any point in time, one of the bidding participants has the highest price of 1,800.
If no other valid bids are available for two days after bidding the yen, then the bid unit is set to 200 yen and only the next bid participant's bid unit is set to 200 yen. In other words, for the next bid participant, 2,000 yen, which is the maximum value of 1,800 + 200, is the effective bid price.

Therefore, also in the present embodiment, the advantage of intentionally performing a rush bid can be reduced by half, and a rush bid intentionally can be eliminated as much as possible. As a result, it is possible to realize an auction environment in which bid participants can maintain fair price formation without causing unfairness.

(Other Embodiments, etc.) The bid price management methods described in the second and third embodiments are each combined with the bid price management method described in the third embodiment. May be implemented. As an example, steps SA2 to SA2 in the first embodiment are described.
In the second embodiment, the processing of SA5 (FIG. 4) is performed in step SB2 or step SB6 shown in FIG.
In the third embodiment, it may be performed immediately before step SC2 or step SC4 shown in FIG.

In this case, and in each of the first to third embodiments, the increase amount of the management bid unit with respect to the above-mentioned bid unit and the bid unit in the management bid unit (actually applied bid unit) are determined. (When application starts)
The setting of the application period may be appropriately set. In addition, although only the case where the change time point and its application period are set in units of days has been described, they may be set in units of hours. In addition, the increase may be determined for each product in accordance with the starting price of the bid set therein, or the change time and the application period may be determined for each product in accordance with the bidding period set at the time of application for exhibition. It may be.

In the above-described embodiment, a general auction in which a bidder bids for the price of a product for sale is described as an example. It is also possible to adopt a so-called reverse auction, in which multiple bid participants lower the selling price of the product for which there is hope, and even in such a case, the advantage of intentionally conducting a rush bid is halved. And eliminate it as much as possible. As a result, it is possible to realize an auction environment in which bid participants can maintain fair price formation without causing unfairness.

[0055]

As described above, in the present invention,
By penalizing a bid just before the deadline,
The benefit of a deliberate last-minute bidding just before the bid deadline can now be halved. Therefore, it is difficult to perform intentional rush bidding, and it is possible to realize an auction environment in which fair price formation can be maintained.

In another embodiment of the present invention, the bid after the intermediate price is continuously maintained is disadvantageous,
The benefits of a deliberate rush bid made shortly before the bid deadline can be reduced. Therefore, it is difficult to perform intentional rush bidding, and it is possible to realize an auction environment in which fair price formation can be maintained.

Another advantage of the present invention is that the advantage of the intentional last-minute bidding immediately before the bidding deadline is reduced by disadvantageous only to the bidding immediately after the intermediate price is continuously maintained. Can be. Therefore, it is difficult to perform intentional rush bidding, and it is possible to realize an auction environment in which fair price formation can be maintained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a network auction system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an auction server.

FIG. 3A is a schematic diagram illustrating a data configuration of a basic bid data file stored in a storage unit, and FIG. 3B is a schematic diagram illustrating a data configuration of a bid management file stored in the storage unit.

FIG. 4 is a flowchart showing a CUP bid price management operation according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing another bid price management operation of the CUP according to the second embodiment of the present invention.

FIG. 6 is a flowchart showing another bid price management operation of the CUP according to the third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 auction server 2 Internet 3 exhibitor terminal 4 bidder terminal 11 CPU 15 storage means 15a basic bid data file 15b bid management file 104 bid unit data 105 maximum price data 106 high price update date and time 107 management bid unit data

Claims (9)

[Claims] Claims 1. A method of managing a bid price in the operation of an auction participating through a communication line, comprising: a step of adding or subtracting from the immediately preceding intermediate price after the remainder of the bidding period reaches a predetermined period. A bid price management method characterized by increasing a price range from before. 2. After the remaining period of the bidding period reaches a predetermined period,
2. The bid price management method according to claim 1, wherein the minimum price range is gradually increased. 3. The bid price management system according to claim 1, wherein the minimum price range is further increased after a predetermined period has elapsed since the highest price was bid. Method. 4. The system according to claim 1, wherein the minimum price range applied to the first bidding immediately after a predetermined period has elapsed since the immediately preceding mid-price was bidding is increased from before. The bid price management method described in 1 or 2. 5. A method of managing a bidding price when operating an auction participating through a communication line, wherein after a predetermined period has elapsed since the bidding of the intermediate price, it can be added or subtracted from the immediately preceding intermediate price. A bid price management method characterized by increasing the minimum price range more than before. 6. A method for managing a bid price in the operation of an auction participating through a communication line, wherein the bid price is applied to a first bidding immediately after a lapse of a predetermined period from the bidding price immediately before. A bid price management method characterized by increasing the minimum price range that can be added to or subtracted from the immediately preceding intermediate price as compared to before. 7. A device used for managing an auction participating through a communication line and managing a bid price, comprising: storage means for storing time limit information on a bid time limit; Calculating means for calculating the remaining period up to the bidding period based on the calculation result; and, when the calculation result of the calculating means becomes a predetermined period, a minimum price range that can be added or subtracted from the immediately preceding intermediate price is set to a larger price than before. A bidding price management device, comprising: setting means for setting a width. 8. A device used for managing an auction participating through a communication line and for managing a bid price, comprising: storage means for storing time limit information regarding a bid time limit; Acquisition means for acquiring a period, With the elapsed period acquired by this acquisition means reaching a predetermined period, the minimum price range that can be added or subtracted from the immediately preceding intermediate price to a larger price range than before A bid price management device, comprising: setting means for setting. 9. An apparatus used for managing an auction participating through a communication line and managing a bid price, wherein the storage means stores expiration date information on a bidding expiration date, and a process since the mid-way price is bid. Acquiring means for acquiring a period, and a minimum price range that can be added to or subtracted from the immediately preceding intermediate price, which is applied to the first bidding immediately after the elapsed period acquired by the acquiring means has reached a predetermined period, Setting means for setting a larger price range than before.