A nonvolatile semiconductor memory device which can shorten data writing and erasing time, significantly improve the endurance characteristic and be activated with low power consumption includes an insulating layer with electric insulation, wherein, a charge retention layer formed adjacent to a tunnel insulating film contains nano-particles comprised of a compound which is constituted from at least one single-element substance or chemical compound having a particle diameter of at most 5 nm functions as a floating gate, and which are independently dispersed with a density of from 10.sup.+12 to 10.sup.+14 particles per square centimeter.