A method of manufacturing a semiconductor device includes the steps of: forming a first metal film on the substrate placed in a processing chamber by alternately supplying at least one type of a metal compound that is an inorganic raw material and a reactant gas that has reactivity to the metal compound to the processing chamber more than once; forming a second metal film on the substrate by simultaneously supplying at least one type of a metal compound that is an inorganic raw material and a reactant gas that has reactivity to the metal compound to the processing chamber once so that the metal compound and the reactant gas are mixed with each other; and modifying at least one of the first metal film and the second metal film is modified using at least one of the reactant gas and an inert gas after at least one of the alternate supply process and the simultaneous supply process. It thus becomes possible to provide a dense, low-resistive metal film having a smooth film surface with a better quality in comparison with a titanium nitride film formed by the CVD method at a higher deposition rate, that is, at a higher productivity, in comparison with a titanium nitride film formed by the ALD method at a low temperature.