PURPOSE: To obtain an apparatus in which the inclination of a tubular member in a thermal treatment furnace is avoided and damages, etc., caused by an intervention between a treated object and the tubular member are avoided by a method wherein a mechanism which retains the tubular member to hold it approximately vertically is provided inside a manifold.

CONSTITUTION: A vertical thermal treatment apparatus has a processing tube 2 which is formed into a cylinder and stood approximately vertically, a manifold 4 which is connected to the lower part of the processing tube 2 and a tubular member 7 which is extended upward from the inside part of the manifold along the inner wall of the processing tube 2. A mechanism which retains the tubular member 7 to hold it approximately vertically is provided inside the manifold 4. For instance, a stainless steel pipe 5 is fixed to the side wall of the manifold 4 by welding, etc., so as to pass through the side wall and a U-shaped notch 6 is provided on the upper side of the end part of the stainless steel pipe 5 inside the manifold 4.