PURPOSE: To simplify the management of cards and to improve payment work by continously executing the paying processing of the total amount of each transaction and the accumulation processing of benefit points only by one card.

CONSTITUTION: When a customer requests payment based upon a card by offer ing a card 30 at the time of purchasing a commodity, an operator in charge inserts the card 30 into a card reader/writer 16 and registers the commodity through a keyboard 22. After the registration, the total amount of the commod ity purchased by the customer and a card balance M1 stored in a RAM are compared with each other and the total amount is subtracted from the balance M1. At that time, a venefit point for the total amount is calculated and added to the accumulated point M2 of the card 30. Thus, the management of the cards can be simplified and the payment work can be improved.