A semiconductor device includes: a substrate having a cell region with a semiconductor element and an outer peripheral region; and a drift layer on the substrate. The semiconductor element includes a base region, a source region, a trench gate structure, a deep layer deeper than a gate trench, a source electrode, and a drain electrode. The outer peripheral region has a recess portion in which the drift layer are exposed, and a guard ring layer. The guard ring layer includes multiple guard ring trenches having a frame shape, surrounding the cell region and arranged on an exposed surface of the drift layer, and a first guard ring in the guard ring trenches. Each of the linear deep trenches has a width equal to a width of each of the linear guard ring trenches.