To enable a customer to carry out an arbitrary transaction process of the financial institution where the customer has an account by expanding the range of transaction processes that ATMs of cooperative financial institutions can handle.

An ATM 402 and a host computer 403 are a transaction processing system of a cooperative financial institution and a host computer 405 is a computer belonging to the financial institution that the customer has an account. In an IC card 401 are stored the financial institution code, transaction guidance screen information and a processing program. When the financial institution code read out of the IC card 401 is one corresponding to the host computer 405, the ATM 402 reads the transaction guidance screen information out of the IC card 401 and displays it, reads the processing program performing a process for the screen out and executes it, and sends inputted transaction information to the host computer 405 through the host computer 403.