Provided is a computation apparatus that is able to adequately obtain a relative value of an incentive point issued by each shop, by computing an exchange rate used in exchanging shop points of the shop into common points. The computation apparatus (25) stores a function for defining the exchange rate (250), and internally maintains, for rate computation, the used house point (UHP) that represents a portion of shop points that has been spent (redeemed) in a shop that has issued the shop points), and the active general point (AGP) that represents a portion of common points that is obtained by exchanging shop points and is not spent yet. A rate function is defined so as to yield a higher exchange rate in exchanging shop points of the shop into common points when the used house point (UHP) of the shop is larger, and to yield a lower exchange rate when the active general point (AGP) of the shop is larger.