The semiconductor device of the present invention includes a bootstrap circuit, the bootstrap circuit including: a selection transistor composed of an n-channel MOS transistor; a booster transistor of which a gate is connected to a drain of the selection transistor; and a boosting circuit that is connected between the gate and a source of the booster transistor, and boosts gate voltage with respect to the source of the booster transistor, wherein gate dimensions of the selection transistor are smaller than gate dimensions of the booster transistor. According to this configuration, the semiconductor device can realize increasing an action of a circuit, decreasing a chip size and simplifying processes.