A semiconductor device includes a substrate having a main surface inclined in an off-direction from a {0001} surface, and a semiconductor layer. The semiconductor layer includes a level difference for alignment mark. An epitaxial layer is disposed on a first portion of the main surface, the first portion being situated on an off-angle upstream side of the level difference, and on a second portion of the main surface, the second portion being situated on an off-angle downstream side of the level difference. A value of |WL−WR| is 1 μm or less, in which WL represents a distance from a center of the level difference to a boundary between an off-angle upstream side corner portion of the level difference and a main surface or a {0001} facet plane generated on the main surface, and WR represents a distance from the center of the level difference to a boundary between an off-angle downstream side corner portion of the level difference and the main surface or the {0001} facet plane generated on the main surface.