An NMOS transistor type nonvolatile semiconductor memory has first and second N-type diffusion layers formed in a P-type silicon layer as a source and a drain; a gate electrode formed on a channel region with an insulating film interposed therebetween, the channel region being sandwiched between the first and second N-type diffusion layers; and a charge storage layer formed in the insulating film. A direction from the first N-type diffusion layer to the second N-type diffusion layer is the same as a crystal orientation of the P-type silicon layer. At the time of rewriting, the hot holes go over a potential barrier of the insulating film to be injected into the charge storage layer.