A semiconductor device includes: a plurality of vertical MOS transistors sharing a gate electrode (2) of a first conductivity type; first semiconductor pillars (3, 4 and 5) with a gate insulating film (18) formed therearound, across the gate insulating film (18) the vertical MOS transistors facing the gate electrode; and a second semiconductor pillar (8) being of the first conductivity type which is the same as the conductivity type of the gate electrode and being in contact with the gate electrode at a portion thereof from which at least a part of the gate insulating film is removed, wherein potential supply (6) to the shared gate electrode (2) is effected through the second semiconductor pillar (8).