An exclusive OR circuit is provided which detects whether or not a preceding-stage logical output value and a subsequent-stage logical output value agree. When these logical output values are found to agree, a NAND circuit functions to cut off the supply of a clock signal to a first and second switch circuits and to a latch circuit. Accordingly, when there occur no data changes between clock signal cycles, in a switch circuit and a latch circuit both arranged between each stage of a pipeline, the charge/discharge of the capacitance of gate electrodes of transistors forming these circuits is prevented, thereby reducing power consumption.