The semiconductor device includes: a plurality of interlayer insulation films, each interlayer insulation film covering a front surface of a corresponding one of the gate electrodes and protruding from the front surface of the semiconductor substrate; the first metal film covering the front surface of the semiconductor substrate and plurality of the interlayer insulation films; and the protective insulation film covering a part of the first metal film. In a cross-section traversing the plurality of trenches, the end of the protective insulation film is above one of the interlayer insulation films, and a width of the one of the interlayer insulation films that is below the end of the protective insulation film is wider than widths of other interlayer insulation films.