The disclosure reduces the risk of collapse of the wall surrounding the trench and suppresses the withstand voltage fluctuation that accompanies the manufacturing variation for a semiconductor device having a super junction structure. The semiconductor device includes a drift layer of a first conductivity type and a plurality of embedded parts embedded in the drift layer. The embedded parts are of a second conductivity type different from the first conductivity type, and the embedded parts are arranged with a first direction as a longitudinal direction and spaced from each other along a second direction that intersects the first direction. A width of each of the embedded parts in the second direction changes continuously along the first direction.