In one embodiment, a semiconductor device includes a substrate, insulating films and first films alternately stacked on the substrate, at least one of the first films including an electrode layer and a charge storage layer provided on a face of the electrode layer via a first insulator, and a semiconductor layer provided on a face of the charge storage layer via a second insulator. The device further includes at least one of a first portion including nitrogen and provided between the first insulator and the charge storage layer with an air gap provided in the first insulator, a second portion including nitrogen, provided between the charge storage layer and the second insulator, and including a portion protruding toward the charge storage layer, and a third portion including nitrogen and provided between the second insulator and the semiconductor layer with an air gap provided in the first insulator.