A silicon carbide semiconductor device includes: a silicon carbide off substrate including a main surface having an off angle relative to a basal plane, the main surface being provided with a trench, the trench having a plurality of side walls and a bottom portion; a gate insulating film covering the side walls and the bottom portion; and a gate electrode provided on the gate insulating film, each of the side walls having an angle of more than 65° and not more than 80° relative to the basal plane in the trench, opening directions of the plurality of side walls being all at a silicon plane side or a carbon plane side.