A fabrication method for a trench type semiconductor device includes: forming a first base layer; forming a gate insulating film on a bottom and sidewall surfaces of a trench; forming a gate electrode for filling up into the trench; covering the gate electrode and forming an interlayer insulating film; forming a second base layer on the first base layer; forming a first main electrode layer on the second base layer; forming a first main electrode which passes through the first main electrode layer by applying the interlayer insulating film as a mask, is connected to the second base layer in the bottom surface of a self-aligned contact trench, and is connected to the first main electrode layer of the self-aligned contact trench; forming a second main electrode layer at a back side of the first base layer; and forming a second main electrode at the second main electrode layer.