The gate electrode is provided on the gate insulating film. The interlayer insulating film is provided to cover the gate electrode. The interlayer insulating film includes a first insulating film which is in contact with the gate electrode, contains silicon atoms, and contains neither phosphorus atoms nor boron atoms, a second insulating film which is provided on the first insulating film and contains silicon atoms and at least one of phosphorus atoms and boron atoms, and a third insulating film which contains silicon atoms and contains neither phosphorus atoms nor boron atoms. The second insulating film has a first surface which is in contact with the first insulating film, a second surface opposite to the first surface, and a third surface which connects the first surface and the second surface. The third insulating film is in contact with at least one of the second surface and the third surface.