PURPOSE: To provide a heat treatment apparatus wherein especially the whole of an object to be treated can be heated at a uniform temperature regarding the heat treatment apparatus wherein the inside of a tank which has housed a heating means capable of heat-treating the object to be treated such as a resist or the like applied to a semiconductor wafer is connected to the insides of a pipe which is set to atmospheric pressure or lower for a gas discharge means.

CONSTITUTION: A heat treatment apparatus is formed by including the following: a heating means 11 which heat-treats an object 31 to be treated at an arbitrary temperature; a treatment yank 12 which has housed the heating means 11 at the inside; and a connection pipe 13 which connects the treatment tank 12 to a gas discharge pipe 14 whose inside is set to atmospheric pressure or lower. In the heat treatment apparatus, the pipe passage of the connection pipe is constituted so as to be freely shut and opened by using an opening and shutting means 21.