A technique includes forming a film containing a first element, a second element and carbon on a substrate by performing a cycle a predetermined number of times. The cycle includes non-simultaneously performing: forming a first layer containing the first element and carbon by supplying a precursor gas having a chemical bond of the first element and carbon from a first supply part to the substrate in a process chamber, and forming a second layer by supplying a reaction gas containing the second element from a second supply part to the substrate in the process chamber and supplying a plasma-excited inert gas from a third supply part to the substrate in the process chamber to modify the first layer, the third supply part being different from the second supply part.