Abstract: A pre-paid vending machine (10) includes a card reader (15) which reads credit data and secret code number from a credit card (11). When a user inputs a secret code number and amount data from an input display (16), whether or not the input secret code number is the same as the secret code number read from the credit card is checked. If the numbers are the same, the input secret code number, the amount data and the like are transmitted to a credit center (13), where it is determined whether or not a credit can be granted. If the credit can be granted, the input amount data is magnetically recorded on the ID card (12) as a credit amount, whereby the ID card can be used as a pre-paid card. When a user buys a thing by inserting the ID card to an automatic vending machine (20), the price of the thing is subtracted from the credit amount of the ID card.