To perform margin supplement processing whose quick and high security is maintained by condensing margin supplement information for executing margin supplement processing.

This credit card margin supplement acting device is provided with a margin supplement information storing means for storing a card number and margin supplement information by associating them with each other, a margin supplement information determination means for determining whether or not margin supplement is stored when the margin supplement information of a card is requested from the terminal equipment of a member store, a margin supplement requesting means for requesting the margin supplement information to a card company, and for storing the acquired margin supplement information in the margin supplement information storing means when the margin supplement of the card whose margin supplement is requested is not stored and a margin supplement responding means for holding the request of the margin supplement information with respect to a card company when the margin supplement information of the card whose margin supplement is requested is stored in the margin supplement information storing means, and for notifying terminal equipment of the stored margin supplement information.