PURPOSE : A system for processing guarantee of a payment tool is provided to enable a customer to receive various kinds of incentives such as increasing a credit limit and enable a card company to offer useful card services to the customer by securing all or a part of financial assets of the customer based on financial asset information stored in a storage medium.CONSTITUTION : An information storing part stores financial asset information of a customer to a storage medium(120) by linking with customer card information. A financial asset information checker(115) checks the financial asset information linked with the payment tool information from in the storage medium when a card(130) is unavailable owing to an exceeded credit limit or a short balance. A card processor(110) adjusts the credit limit or processes an approval for using the card based on a guarantee tool by setting all or a part of financial assets of the customer as the guarantee tool based on the checked financial asset information. The financial asset information includes more than one of balance information, real estate/estate information, and stock or bond information of the customer.? KIPO 2008