A method of manufacturing a semiconductor device comprises forming a gate insulation film on a semiconductor substrate; forming a first gate electrode and a second gate electrode on the gate insulation film; forming a mask material so as to expose an upper surface of the first gate electrode while keeping the second gate electrode covered; etching an upper part of the first gate electrode by using the mask material as a mask; removing the mask material; depositing a metal film on the first gate electrode and the second gate electrode; and siliciding the whole of the first gate electrode and an upper part of the second gate electrode.