PURPOSE: To attain the transaction of an automatic cash transaction device through a storage medium by previously storing transaction data in the storage medium by using a personal computer.

CONSTITUTION: The automatic cash transaction device 1 and the personal computer 10 are respectively provided with storage medium reading/writing mechanisms 6, 14. At the time of preparing a storage medium, the device 1 writes a transaction data writing program and a group of transaction data in an inserted storage medium and the computer 10 reads out the transaction data writing program from the inserted storage medium, prepares transaction data based upon the input data and writes the prepared data in the storage medium in accordance with the program. At the time of executing storage medium transaction, the device 1 reads out the transaction data from the transaction data group stored in the inserted storage medium and executes transaction processing based upon the transaction data.