A method of fabricating a semiconductor device according to an embodiment includes: forming a precursor film containing therein a predetermined metallic element on a surface of a recess portion formed in an insulating film on a semiconductor substrate; forming a wiring formation film on the precursor film; performing a heat treatment in an oxidation ambient atmosphere to cause the precursor film and the insulating film to react with each other, thereby forming a self-formed barrier film containing a compound, containing therein the predetermined metallic element and a constituent element of the insulating film, as a basic constituent in a boundary surface between the precursor film and the insulating film, and moving the predetermined metallic element unreacted into the wiring formation film through diffusion to cause the predetermined metallic element unreacted to react with oxygen contained in the oxidation ambient atmosphere on a surface of the wiring formation film, thereby precipitating an unreacted metallic oxide film including the predetermined metallic element; forming the same material as that of the wiring formation film on the wiring formation film after the unreacted metallic oxide film is removed; and flattening the wiring formation film until a portion of the insulating film located outside the recess portion is exposed.