A nonvolatile semiconductor memory according to an aspect of the invention comprises a semiconductor substrate which has an SOI region and an epitaxial region at its surface, a buried oxide film arranged on the semiconductor substrate in the SOI region, an SOI layer arranged on the buried oxide film, a plurality of memory cells arranged on the SOI layer, an epitaxial layer arranged in the epitaxial region, and a select gate transistor arranged on the epitaxial layer, wherein the SOI layer is made of a microcrystalline layer.