An operation signal generating unit 11 and a reset unit 12 are included in a first circuit unit 10 that operates based on a first power supply voltage V1 and an output operation of a second power supply voltage B2 is stopped by outputting a reset signal Sr from the reset unit 12 to a regulator 20 in accordance with an operation signal Si of the operation signal generating unit 11. Hence, unlike a conventional technique, a large transistor for cutting off a power supply line is unnecessary, and therefore a device size can be reduced.