PURPOSE: To obtain an apparatus which does not cause the leakage of exhaust gas and the breakage of an exhaust piping system and has improved reliability by a method wherein a heat-resistant pipe which is bent at two or more positions is connected to a gas outlet part and the heat-resistant pipe is connected to an exhaust pipe through a flexible pipe made of fluorine resin.

CONSTITUTION: A thermal treatment apparatus has a processing tube 20 which is formed into a cylinder and has an exhaust gas outlet part 21 on its side wall and a heater which is so provided as to surround the outside of the processing tube 20. A heat-resistant pipe 22 which is bent at two or more positions is connected to the gas outlet part 21 and the heat-resistant pipe 22 is connected to an exhaust pipe 22 through a flexible pipe 23 made of fluorine resin. For instance, the exhaust gas outlet part 21 which is so provided as to protrude from the side wall of the processing tube 20 of a thermal treatment furnace 2 is connected to the exhaust pipe 12 through a bent quartz pipe 22 which is the heat-resistant pipe and the bellows-type flexible pipe 23 made of fluorine resin which has corrosion-resistance against oxidizing gas such as HCl gas.