A semiconductor device includes: a plurality of n type pillar regions and an n− type epitaxial layer disposed on a first surface of an n+ type silicon carbide substrate; a p type epitaxial layer and an n+ region disposed on the plurality of n type pillar regions and the n− type epitaxial layer; a trench penetrating the n+ region and the p type epitaxial layer and disposed on the plurality of n type pillar regions and the n− type epitaxial layer; a gate insulating film disposed within the trench; a gate electrode disposed on the gate insulating film; an oxide film disposed on the gate electrode; a source electrode disposed on the p type epitaxial layer, the n+ region, and the oxide film; and a drain electrode disposed on a second surface of the n+ type silicon carbide substrate, wherein each corner portion of the trench is in contact with a corresponding n type pillar region.