According to one embodiment, a semiconductor device includes a substrate, a stacked body, a second air gap, a first insulating film, a semiconductor film, and a stacked film. The stacked body is provided above the substrate and includes a plurality of electrode films stacked via a first air gap. The second air gap extends in a stacking direction of the stacked body. The second air gap separates the stacked body in a first direction crossing the stacking direction. The first insulating film is provided above the stacked body and covers an upper end of the second air gap. The stacked film is provided between a side surface of the electrode film and a side surface of the semiconductor film opposed to the side surface of the electrode film. The stacked film is in contact with the side surface of the electrode film and the side surface of the semiconductor film.