Wells formed in a semiconductor device can be discharged faster in a transition from a stand-by state to an active state. The semiconductor device includes an n-type well applied, in an active state, with a power supply voltage and, in a stand-by state, with a voltage higher than the power supply voltage, a p-type well applied, in the active state, with a ground voltage and, in the stand-by state, with a voltage lower than the ground voltage, and a path which, in a transition from the stand-by state to the active state, electrically couples the n-type well and the p-type well.