There is provided a technique which includes: forming a film containing at least Si, O and N on a substrate in a process chamber by performing a cycle a predetermined number of times, the cycle including non-simultaneously performing: forming a first layer by supplying a precursor gas containing at least a Si—N bond and a Si—Cl bond and a first catalyst gas to the substrate; exhausting the precursor gas and the first catalyst gas in the process chamber through an exhaust system; forming a second layer by supplying an oxidizing gas and a second catalyst gas to the substrate to modify the first layer; and exhausting the oxidizing gas and the second catalyst gas in the process chamber through the exhaust system.