To suppress current leakage in a semiconductor device having a gate insulating film and a gate electrode. A gate electrode is continuously formed in a film via a gate insulating film on the bottom surface of a trench, the side surfaces of a trench, and the top surfaces of a second n-type layer in the vicinity of the side surfaces of the trench. The ends of the bottom surface of the gate electrode are aligned with the ends of the top surface of the gate insulating film, and the ends of the bottom surface of the gate insulating film are formed in contact with the surfaces of the second n-type layer facing the ends of the bottom surface of the gate electrode. The passivation film covers the entire top surface of the device except the contact holes of the gate electrode and the source electrode.