To provide a card processor for purchasing merchandise even when foreign currency is used by converting foreign currency payment selling sum into yen at a set rate, and operating adjustment.

A processing program corresponding to denomination is stored in a card reader/writer 2 for operating reading and writing to a magnetic recording part 12 of a card 1, and when a system card 1A is identified, a rate setting mode is obtained by a designating operation by a key inputting part 23, and the numerical value of an exchange rate is set. Afterwards, at the time of foreign currency payment selling with a pre-paid card 1C, the sum is converted into yen based on the set rate, and data after the sum is subtracted in each yen unit are printed and recorded in the card.