To certify the completion of payment and to prevent the occurrence of repayment of a charge, a dispute affair between persons concerned in a transaction or the like.

When payment has been completed, payment information and inputted handwritten signature data are stored in the payment information areas of both IC cards. In the case of preparing a paid certification, the payment information data stored in the payment information areas of both the IC cards are collated with each other to judge whether the contents are the same or not and collate the handwritten signature data. Thus the completion of payment can be surely certified and the occurrence of the repayment of a charge, a dispute affair between both persons concerned with the transaction or the like can be prevented.