PURPOSE: To permit the exchange of a battery while retaining the memory of the data of a RAM type IC memory card.

CONSTITUTION: An IC memory card is connected to a connector 6 and a fixing part 7, fixed under exchangeable condition of a battery physically without covering the battery receiving part of the IC memory card, is fixed to a main body 1. Next, an operating electric power is supplied to the IC memory card from a power supply, accommodated in the main body 1, through a constant voltage circuit and the connector 6 when a switch 9 is put ON whereby operating power supplying condition is shown by a power supply indicator 10. In this case, the memory retaining power supply for the IC memory card is switched from the battery in the IC memory card into an operating power supplied from a main device whereby memory can be retained even when the battery is separated. Accordingly, the battery can be exchanged without any trouble, such as unwillful drop-out of the IC memory card during the exchanging work of the battery and losing of the memory of the same, when the exchange of the battery for the IC memory card is effected while employing the title device.