A semiconductor device of the present invention is a semiconductor device selectively including a nonvolatile memory cell on a semiconductor substrate, and includes a trench formed in the semiconductor substrate, an element separation portion buried into the trench such that the element separation portion has a projecting part projecting from the semiconductor substrate, the element separation portion defining an active region in first a region for the nonvolatile memory cell of the semiconductor substrate, and a floating gate disposed in the active region such that the floating gate selectively has an overlapping part overlapping the element separation portion, and the floating gate has a shape recessed with respect to the overlapping part.