PURPOSE: To leave effective transaction history obtained until the face value of a prepaid card is used up without lacking the number of printing lines by setting up a printing condition, and only when the condition is satisfied, printing out the balance of the prepaid card.

CONSTITUTION: A transaction reservation discriminating part 3 discriminates whether a transaction reserving amount is zero or not, an arithmetic part 4 executes various arithmetic such as a printing using amount and others and a printing condition discriminating part 5 discriminates whether the printing of the balance is to be executed based on the prescribed printing condition or not. The transaction reserving amount means the accumulated amount of unprinted transaction using amounts and the printing using amount is a value obtained by dividing the printed balance by the printable lines of the prepaid card. The printing condition is transaction using amount ≥ printing using amount - transaction reserving amount, and when the printing condition is satisfied, the discrimination of the printing condition becomes true. Consequently, effective transaction history obtained until the face value of a prepaid card is used up can be left.