Abstract: A method of manufacturing a semiconductor device according to an embodiment, includes: forming a stack structure by alternately stacking control gate electrodes and interlayer insulating films; forming a through-hole that penetrates through the stack structure in a stacking direction of the control gate electrodes and the interlayer insulating films; forming a first insulating film that covers an inner surface of the through-hole; forming a charge storage layer that covers an inner surface of the first insulating film; forming a second insulating film that covers an inner surface of the charge storage layer; forming a semiconductor layer that covers an inner surface of the second insulating film; and oxidizing an interface between the semiconductor layer and the second insulating film by performing a heat treatment in an atmosphere containing O2 gas at a temperature of 600° C. or lower.