A nonvolatile memory which has both the merits of a floating gate type EEPROM and an MNOS type EEPROM and which can be written into and erased with low voltages is disclosed. Each memory element in the nonvolatile memory has a floating gate, a control gate, a gate insulator film between a semiconductor body and the floating gate, and an inter-layer insulator film between the control gate and the floating gate. The gate insulator film is made up of a very thin SiO.sub.2 film and a thin Si.sub.3 N.sub.4 film formed thereon. The charge centroid of charges injected for storing data lies within the floating gate, not within the Si.sub.3 N.sub.4 film.