Abstract: A method of manufacturing a semiconductor device includes providing a substrate having an insulating film and a plurality of conductive films on a surface; reducing the substrate by supplying a first reducing gas to the substrate so that at least one of a plurality of process conditions of the first reducing gas is controlled so that a product of a plurality of process conditions becomes a predetermined value, wherein the process conditions of the first reducing gas include a partial pressure of the first reducing gas in a region where the substrate exists and a time taken to supply the first reducing gas to the substrate corresponding to a temperature of the first reducing gas; and selectively forming a metal film on the plurality of the reduced conductive films by supplying a second reducing gas and a metal-containing gas to the substrate.