According to the embodiment, a semiconductor device includes: a stacked body; a columnar portion, an insulating portion; and wall portion. The stacked body includes a plurality of electrode layers stacked with an insulator interposed. The columnar portion is provided in the stacked body and extends in a staking direction of the stacked body. The insulating portion is provided around the stacked body and surrounds the stacked body. The wall portion is provided in the insulating portion and is separated from the stacked body. The wall portion extends in the stacking direction and in a first direction crossing the stacking direction.