Abstract: A heat-treatment apparatus of the invention includes a collective exhaust unit for constantly performing gas exhaust from a clean room to keep the room in a clean atmosphere, a heat-treatment furnace for receiving a gas and/or a liquid for forming a desired film on a surface of an object to be treated in a heating atmosphere, an exhaust path, communicating with the collective exhaust unit and the heat-treatment furnace, for introducing a gas filling the heat-treatment furnace into the collective exhaust unit, an outer air intake unit for taking in outer air in the exhaust path to adjust an exhaust pressure of the exhaust path, and a trap unit, arranged below the exhaust path, for trapping a waste liquid collected in the exhaust path.