On top of respective areas divided by partition plates, that is, a cassette
station, a processing station, and an interface section in a coating and
developing processing system, gas supply sections for supplying an inert
gas into the respective areas are provided. Exhaust pipes for exhausting
atmospheres in the respective areas are provided at the bottom of the
respective areas. The atmospheres in the respective areas are maintained
in a clean condition by supplying the inert gas not containing impurities
such as oxygen and fine particles from the respective gas supply sections
into the respective areas and exhausting the atmospheres in the respective
areas from the exhaust pipes.