A system is provided which compensates a low operational performance of a conventional integrated circuit (IC) card by setting a substitute server computer between the IC card and a business server computer in a system using the IC card. Substitute processing using an authentication result is realized by setting an IC card authentication server computer in addition to the business server computer and sending an authentication result of the authentication server computer to the IC card, substitute server computer, and business server computer. Thus, because the substitute server computer does not directly authenticate the IC card, the quantity of authentication information in the substitute server computer is substantially reduced and authentication processing becomes efficient.