Disclosed herein is a semiconductor device that includes a semiconductor substrate, a drift layer formed on the semiconductor substrate, a first electrode in contact with the drift layer, and a second electrode in contact with the semiconductor substrate. The drift layer has: a plurality of outer peripheral trenches including a first outer peripheral trench formed along an outer edge of the first electrode so as to overlap the outer edge in a plan view and a second outer peripheral trench formed adjacent to the first outer peripheral trench and outside the first outer peripheral trench so as to surround the first outer peripheral trench in a plan view; and a first mesa region located between the first outer peripheral trench and the second outer peripheral trench. The first mesa region has a smaller width than the first outer peripheral trench.