PURPOSE: To heat-treat a material without damage due to impurities from an elevation mechanism to the material to be treated by disposing the mechanism in the outer atmosphere, shutting OFF a material-to-be-treated holder from the atmosphere by an extensible bellowslike tube, and disposing it in the same atmosphere as that in a treating vessel.

CONSTITUTION: An elevation mechanism 4 is disposed in the outer atmosphere. A wafer holder 3 is shut OFF from the atmosphere by an extensible bellowslike tube 5, and disposed in the same atmosphere as that in a treating vessel. Damage of a semiconductor wafer 1 due to impurities from the mechanism 4 is prevented, and the wafer is smoothly heat-treated. The mechanism 4 is disposed in the atmosphere without sealing to reduce a volume of an entire apparatus. Thus, a material to be treated can be heat-treated without damage due to the impurities from the mechanism, a volume of a space to be evacuated is reduced to decrease in size an exhaust unit.