The semiconductor device according to the present invention includes a semiconductor layer of a first conductivity type made of SiC, a body region of a second conductivity type formed on a surface layer portion of the semiconductor layer, a gate trench dug down from a surface of the semiconductor layer with a bottom surface formed on a portion of the semiconductor layer under the body region, source regions of the first conductivity type formed on a surface layer portion of the body region adjacently to side surfaces of the gate trench, a gate insulating film formed on the bottom surface and the side surfaces of the gate trench so that the thickness of a portion on the bottom surface is greater than the thickness of portions on the side surfaces, a gate electrode embedded in the gate trench through the gate insulating film, and an implantation layer formed on a portion of the semiconductor layer extending from the bottom surface of the gate trench to an intermediate portion of the semiconductor layer in the thickness direction by implantation of a second conductivity type impurity.