A semiconductor device includes a first circuit block connected between first and second power lines, a logic circuit that receives an output signal of the first circuit block that is connected between the first power line and a fourth power line or a third power line and the second power line, and a second circuit block that receives an output signal of the logic circuit that is connected between the third and fourth power lines. In an active state, a first potential is supplied and in a standby state, a second potential lower than the first potential is supplied between the first and second power lines. In any of the active state and the standby state, the first potential is supplied between the third and fourth power lines. With this configuration, speeding-up of a critical path can be realized while maintaining a subthreshold current low.