There is provided a technique that includes: processing a substrate in a process vessel by supplying a processing gas to the substrate and exhausting the processing gas from an exhaust part including an exhaust pipe and a pump; cleaning an interior of the exhaust part by supplying a first cleaning gas from a supply port installed in the exhaust pipe directly into the exhaust pipe; and cleaning an interior of the process vessel by supplying a second cleaning gas into the process vessel, wherein a frequency of performing the act of cleaning the interior of the exhaust part is set higher than a frequency of performing the act of cleaning the interior of the process vessel.