A p-type collector region of an IGBT and an n-type cathode region of a free wheel diode are alternately formed in a second main surface of a semiconductor substrate. A back electrode is formed on the second main surface so as to be in contact with both of the p-type collector region and the n-type cathode region, and has a titanium layer, a nickel layer and a gold layer that are successively stacked from the side of the second main surface. A semiconductor device capable of obtaining a satisfactory ON voltage in any of conduction of an insulated gate field effect transistor and conduction of the free wheel diode as well as a manufacturing method thereof can thus be obtained.