Abstract: A semiconductor device includes: a substrate with an off-angle; an SiC layer provided on a principal surface of the substrate, including an n type drift region, and having a trench whose bottom is located in the drift region; and a gate electrode provided in the trench in the SiC layer. In the trench in the SiC layer, a first angle formed by at least part of a first sidewall on an off-direction side and the principal surface of the substrate is an obtuse angle, and a second angle formed by at least part of a second sidewall opposite to the first sidewall and the principal surface of the substrate is an acute angle, in a cross section parallel to a direction of a normal line to the principal surface of the substrate and a direction of a c-axis of the substrate.