Provided is a technique for forming a film having a desired stress on a substrate. A method of manufacturing a semiconductor device includes: forming a film having a predetermined stress on a substrate by controlling a ratio of a thickness of a first film having compressive stress to a thickness of a second film having tensile stress by performing: (a) supplying an organic source gas containing a first element and a reactive gas containing a second element to the substrate to form the first film containing the first element and the second element; and (b) supplying an inorganic source gas containing the first element and the reactive gas to the substrate to form the second film containing the first element and the second element.