Performances of a semiconductor device are improved. The semiconductor device has: a gate electrode formed on an SOI layer of an SOI substrate via a gate insulating film having a charge storage film therein; an n-type semiconductor region and a p-type semiconductor region respectively formed on SOI layers on both sides of the gate electrode. A memory cell MC serving as a non-volatile memory cell is formed of the gate insulating film, the gate electrode, the n-type semiconductor region and the p-type semiconductor region.