To provide a heat treatment device having a comparatively simple configuration, and inhibiting the production of so-called sublimate produced when a produced gas generated in accompany with the heat treatment of a base plate is cooled.

This heat treatment device 1 has an air adjusting part 11 comprising a hot water supplying means 14 for allowing a base plate treatment part 5 to supply the hot air, and a heat treatment chamber 12 for heat treatment of the base plate. The heat treatment device 1 is provided with a catalyst wall 40 holding a catalyst promoting oxidative dissolution of the produced gas generated at a downstreammost side of the heat treatment chamber 12 in treating the base plate. Thus the production of the so-called sublimate produced when the produced gas is cooled, can be remarkably reduced in this heat treatment device 1. Further as the reaction heat is generated in oxidative dissolution of the produced gas, the consumption of electric power necessary for heating a mixed gas in the heat treatment can be reduced.