According to one embodiment, a semiconductor device includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of the first conductivity type, a third semiconductor layer of a second conductivity type, a fourth semiconductor layer of the second conductivity type, a fifth semiconductor layer of the first conductivity type, a control electrode, a first main electrode, a second main electrode, and a sixth semiconductor layer of the first conductivity type. The second semiconductor layer and the third semiconductor layer are alternately provided on the first semiconductor layer in a direction substantially parallel to a major surface of the first semiconductor layer. The fourth semiconductor layer is provided on the second semiconductor layer and the third semiconductor layer. The fifth semiconductor layer is selectively provided on a surface of the fourth semiconductor layer. The control electrode is provided in a trench via an insulating film. The trench penetrates through the fourth semiconductor layer from a surface of the fifth semiconductor layer and is in contact with the second semiconductor layer. The first main electrode is connected to the first semiconductor layer. The second main electrode is connected to the fourth semiconductor layer and the fifth semiconductor layer. The sixth semiconductor layer is provided between the fourth semiconductor layer and the second semiconductor layer. An impurity concentration of the sixth semiconductor layer is higher than an impurity concentration of the second semiconductor layer.