Supply of power to a plurality of circuits is controlled efficiently depending on usage conditions and the like of the circuits. An address monitoring circuit monitors whether a cache memory and an input/output interface are in an access state or not, and performs power gating in accordance with the state of the cache memory and the input/output interface. The address monitoring circuit acquires and monitors an address signal between a signal processing circuit and the cache memory or the input/output interface periodically. When one of the cache memory and the input/output interface is in a standby state and the other is in the access state, power gating is performed on the circuit that is in the standby state.