CARD-TYPE STORAGE MEDIUM

A non-volatile memory installed inside an IC card having a main area and a temporary storage area. The main area is the area in which data is referred to by a host computer. The temporary storage area is the area in which data is transmitted and written by the host computer. Data from the host computer is copied to the main area after being written once in the temporary storage area. Further, data inside the temporary storage area which has not been yet copied is then copied to the main area at the time of power-up. Therefore, even if a power interruption occurs while data is input from the host computer to the IC card, data inside the main area is never destroyed and data inside the main area can be restored based on data remaining in the temporary storage area.