There is provided a technique that includes: loading an m-th substrate into a process chamber, wherein m is an integer less than n; forming a film on the m-th substrate by heating the m-th substrate in the process chamber; unloading the m-th substrate from the process chamber; waiting for a predetermined time in the process chamber, in a state where the substrates are not present in the process chamber, after the act of unloading; loading a next substrate, which is one of the n substrates to be processed next, into the process chamber, after the act of waiting; and forming a film on the next substrate by heating the next substrate in the process chamber.