A semiconductor substrate having a main surface, first and second floating
gates formed spaced apart from each other on the main surface of the
semiconductor substrate, first and second control gates respectively
located on the first and second floating gates, a first insulation film
formed on the first control gate, a second insulation film formed on the
second control gate to contact the first insulation film, and a gap
portion formed at least between the first floating gate and the second
floating gate by achieving contact between the first insulation film and
the second insulation film are included. With this, a function of a
nonvolatile semiconductor device can be ensured and a variation in a
threshold voltage of a floating gate can be suppressed.