A method of manufacturing a semiconductor device includes in the following order: a semiconductor base body preparing step; a first trench forming step; a first insulation film forming step; a gate insulation film forming step; a gate electrode forming step; a second trench forming step of forming a second trench in the inside of a first trench by removing a center portion of the first insulation film; a second insulation film forming step of forming a second insulation film in the inside of the second trench under a condition that a first gap remain in the inside of the second trench; a shield electrode forming step of forming a shield electrode in the inside of the first gap; a shield electrode etching back step of forming a second gap; and a source electrode forming step of forming a source electrode.