To increase the opportunities for contribution and the amount of contribution.

This charge calculating device is provided with a user-setting means for setting a user-contributing money, a payment detecting means for detecting the occurrence of predetermined payment by the user, and an amount claimed calculating means for calculating the amount claimed for the user, by adding the amount of predetermined contribution to the charge of payment, when the payment detecting means detects the occurrence of payment by the user and set by the user-setting means.