A semiconductor device includes a chip having a principal surface, a first conductivity type drift region formed at a surface layer portion of the principal surface, a trench electrode type gate structure formed on the principal surface such as to be placed in the drift region, and a second conductivity type well region formed along a bottom wall of the gate structure in a region below the gate structure in the drift region, wherein the well region includes a plurality of first well regions each of which is a first well region having a first bottom portion having a first depth and which are formed at an interval of a first interval from each other in a depth direction of the gate structure, and the first well regions adjacent each other face each other in the depth direction of the gate structure across a portion of the drift region.