A semiconductor device includes a semiconductor substrate. A gate electrode is formed on the semiconductor substrate via a gate insulating film. A source region and a drain region of a first conductivity type are formed on the first side and the second side of the gate electrode, respectively, in the semiconductor substrate. A punch-through stopper region of a second conductivity type is formed in the semiconductor substrate such that the second conductivity type punch-through stopper region is located between the source region and the drain region at distances from the source region and the drain region and extends in the direction perpendicular to the principal surface of the semiconductor substrate. The concentration of an impurity element of the second conductivity type in the punch-through stopper region is set to be at least five times the substrate impurity concentration between the source region and the drain region.