A valve device includes: valves configured to control a flow of processing gases supplied to a process vessel; a housing in which first flow paths through which the processing gases flow are formed; a heat diffuser configured to cover the housing and diffuse heat of the housing; a heating part configured to cover the housing covered with the heat diffuser and heat the housing via the heat diffuser; a supply configured to supply a coolant to a second flow path formed between the housing and the heat diffuser; and a controller configure to control the heating part to heat the housing to a first temperature when a predetermined process is performed on a target substrate, and before a start of a cleaning process of the process vessel, control the heating part to stop heating of the housing and control the supply to supply the coolant to the second flow path.