A method of manufacturing a semiconductor device provided with an interlayer insulating film formed on a semiconductor substrate, and a plurality of wiring layers formed on the interlayer insulating film. The method includes forming of a first wiring layer closest to the semiconductor substrate among the plurality of wiring layers, and forming of an alloy of a titanium layer and a metal layer by heating treatment. The forming of the first wiring layer includes: forming of a titanium layer on an interlayer insulating film; forming of a metal layer containing a metal capable of forming an alloy with titanium in the titanium layer; forming of an orientation layer on the metal layer; and forming of an aluminum layer on the orientation layer.