Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a plurality of gate electrode structures formed on a semiconductor substrate and an insulating film which covers the gate electrode structures and has an air gap in it. Each of the gate electrode structures includes a gate insulting film, a charge storage layer, an intermediary insulating film, and a control gate electrode. The control gate electrode includes a first control gate and a second control gate whose width is greater than that of the first control gate. The air gap is formed so as to be higher than a space between the control gate electrodes and than the control gate electrodes.