It is intended to provide an A/D converter circuit with which, by using a clock signal, on the basis of an analog voltage inputted a predetermined time past, it is possible to select suitably comparators to be operated and comparators to be rested, and which has small consumed power. A parallel-type A/D-converter circuit 200 converts an analog voltage VIN to a digital value DOUT at intervals of a predetermined period by means of a clock signal CLK using chopper-type comparators 1–7. The comparators 1–7 can each be set by first and second setting signals CONT1A etc. to either of an operating state and a resting state. A comparator control circuit section 211 performs logical processing on the comparator outputs OUT1–OUT7 in the preceding conversion to generate the first and second setting signals CONT1A etc., and brings some of the comparators to the operating state and holds the remaining comparators in the resting state.