There is provided a technique that includes: forming a film on a substrate including a recess formed on a surface of the substrate by performing a cycle a predetermined number of times, the cycle including: (a) supplying a precursor gas to the substrate; and (b) supplying a reaction gas to the substrate, wherein in (a), the precursor gas is supplied to the substrate separately a plurality of times, and a processing condition under which the precursor gas is supplied for a first time is set to a processing condition under which self-decomposition of the precursor gas is capable of being more suppressed than a processing condition under which the precursor gas is supplied for at least one subsequent time after the first time.