An air-supply machine cleans outside air. The cleaned outside air is dehumidified by cooling by performing heat exchange between the cleaned outside air and an exhaust air from a lithography apparatus by a first heat-pipe. The dehumidified outside air is heated by performing heat treatment between the dehumidified outside air and an exhaust air from a vertical heat treatment apparatus by a second heat-pipe. The heated outside air is supplied to inside the housing of the vertical heat treatment apparatus. Thereby, the consumption of air in the clean room is reduced and the running cost of the clean room is reduced.