PURPOSE: To prevent a card unit from being misrecognized due to simultaneous accesses from a CPU and a host for controlling the card unit to a shared memory at the time of transferring card attribute information stored in a ROM for storing a program and to smoothly transfer the card attribute information to the shared memory.

CONSTITUTION: When a program starts processing for transferring card attribute information 17 stored in the ROM 16 for storing a program code in the shared memory, the CPU 12 outputs an access inhibition signal to inhibit an access from the host 14 to a memory 13 and transfers' the information 17 stored in the ROM 16 to the memory 13. At the time of ending the transfer of the information 17 from the ROM 16 to the memory 13, the CPU 12 stops the output of the access inhibition signal and permits an access from the host 14 to the memory 13.