Abstract: It is possible to prevent the deterioration of device characteristic as much as possible. A semiconductor device includes: a semiconductor substrate; a gate insulating film provided above the semiconductor substrate and containing a metal, oxygen and an additive element; a gate electrode provided above the gate insulating film; and source/drain regions provided in the semiconductor substrate on both sides of the gate electrode. The additive element is at least one element selected from elements of Group 5, 6, 15, and 16 at a concentration of 0.003 atomic % or more but 3 atomic % or less.