A nonvolatile semiconductor memory device includes a semiconductor substrate, a first floating gate formed on a main surface of the semiconductor substrate, a second floating gate formed on the main surface of the semiconductor substrate, a first control gate formed on the first floating gate, a second control gate formed on the second floating gate, an interlayer insulating film, and a gap formed in the interlayer insulating film in at least a portion located between the first and second floating gates. Accordingly, a nonvolatile semiconductor memory device for which variations in threshold voltage of a memory cell can be suppressed and an appropriate read operation can be carried out, as well as a method of manufacturing the nonvolatile semiconductor memory device are provided. Further, a capacitance formed between interconnect lines can be reduced and the drive speed can be improved.