A semiconductor device provides an element arrangement region on a semiconductor substrate including: a first semiconductor region on the semiconductor substrate; a second semiconductor region on the first semiconductor region; multiple trench gates penetrating the first semiconductor region and reaching the second semiconductor region; a third semiconductor region contacting the trench gate; a fourth semiconductor region on a rear surface; a first electrode connected to the first and second semiconductor regions; and a second electrode connected to the fourth semiconductor region. Each trench gate includes a main trench gate for generating a channel and a dummy trench gate for improving a withstand voltage of a component. The device further includes: a dummy gate wiring for applying a predetermined voltage to the dummy trench gate; and a dummy pad connected to the dummy gate wiring. The dummy pad and the first electrode are connected by a conductive member.