Provided is a technique including forming a film on a substrate, the film including a first element and a second element different from the first element, by performing a cycle a predetermined number of times. The cycle includes: forming a first layer including a discontinuous chemical adsorption layer of a molecule constituting a gas containing the first element by supplying the gas containing the first element to the substrate under a condition where chemical adsorption of the molecule on a surface of the substrate is not saturated; and forming a second layer including the first element and the second element by supplying a gas containing the second element to the substrate to modify the first layer under a condition where a modifying reaction of the first layer by the gas containing the second element is not saturated.