To make it possible to reliably halt writing processing while restraining erroneous writing to the memory unit, present apparatus has a memory unit to which data is written for each write request; a voltage converting unit which converts a first power source voltage into a first operable voltage with which a write request issuing unit is operable, and supplies the first operable voltage to the write request issuing unit; a voltage monitoring unit, which outputs an issuance restraining signal which restrains issuance of the write request, when the first power source voltage becomes lower than a reference voltage; and an issuance restrain controlling unit which receives the issuance restrain signal, and then after completion of writing for each of the write request to write memory unit, which restrains the issuance of the write request by the write request issuance unit.