A semiconductor device includes a body region, a drift region having a first part and a second part, and a trench gate electrode. The body region is disposed on the drift region. The first and second parts extend in an extending direction so that the second part is adjacent to the first part. The trench gate electrode penetrates the body region and reaches the drift region so that the trench gate electrode faces the body region and the drift region through an insulation layer. The trench gate electrode extends in a direction crossing with the extending direction of the first and second parts. The first part includes a portion near the trench gate electrode, which has an impurity concentration equal to or lower than that of the body region.