A semiconductor device includes: a semiconductor substrate; a first semiconductor layer; a first conductor; a first power supply line; a second power supply line; and a circuit. The semiconductor substrate has a first surface, a second surface facing the first surface, and a third surface disposed between the first surface and the second surface. The first semiconductor layer is disposed along the first surface from the third surface. The first conductor is disposed on the first semiconductor layer. The first power supply line is electrically connected to the first conductor. The second power supply line is electrically connected to the semiconductor substrate. The circuit is disposed on the semiconductor substrate and connected to the first power supply line and the second power supply line.