PURPOSE: To secure balance data of the card for card type automatic vending machines to a fixed extent even when such a trouble as power failure, etc., occurs, with a mischief preventive measure being taken, by recording the balance calculated by subtracting a fixed amount required for selling a commodity from the amount data of a card and, after the commodity is sold, rewriting the sum of the balance and the amount calculated by subtracting the price of the commodity from the fixed amount on the card.

CONSTITUTION: Means 2 and 3 which subtract a fixed amount required for selling a commodity from the amount data of a card 1 before selling the commodity after reading the amount data from the card and write the balance data on the card 1 are provided. The means 2 and 3 are also used for subtracting the price of the commodity from the fixed amount and write the sum of the balance and the written balance on the card 1 after the commodity is sold. Since the fixed amount is subtracted before making a sale in such way, a mischief preventive measure is taken even when the card 1 is removed during the course of a sale. In addition, security is also expected even when such a trouble as power failure, etc., occurs during the course of a sale, since the balance is written on the card after the fixed amount is subtracted. Therefore, the balance data can be secured to such extent.