Abstract: There is provided a technique that includes: forming a film on a substrate in a process chamber by performing a cycle a predetermined number of times, the cycle including non-simultaneously performing: (a) supplying a precursor from a first supplier to the substrate and exhausting the precursor from an exhaust port installed opposite to the first supplier with the substrate interposed between the exhaust port and the first supplier; and (b) supplying a reactant from a second supplier to the substrate and exhausting the reactant from the exhaust port, wherein in (a), inert gas is supplied into the process chamber from a third supplier installed at a region, which is a region on a side of the exhaust port among a plurality of regions partitioned in the process chamber by a bisector perpendicular to straight line connecting the first supplier and the exhaust port in a plane view.