Electric-field concentration in the vicinity of a recess is suppressed. A gate insulating film is provided on a substrate that has a drain region and a first recess therein. The first recess is located between the gate insulating film and the drain region, and is filled with an insulating film. The insulating film has a second recess on its side close to the gate insulating film. An angle defined by an inner side face of the first recess and the surface of the substrate is rounded on a side of the drain region close to the gate insulating film.