PURPOSE: To make odorous gas generated at the time of degreasing harmless by providing a high temperature baking chamber and a low temperature degreasing chamber continued to upper and lower positions in a furnace body, and providing a moving member placing a material to be treated and moving between the degreasing chamber and the baking chamber.

CONSTITUTION: A ceramic material is degreased in a low temperature degreasing chamber 3. In this case, when the material is degreased while supplying degreasing gas G1 by communicating a degreasing gas supply tube 6, a baking gas supply tube 22 and degreasing gas exhaust tube 23, odorous gas is generated from the material. Then the odorous gas is introduced together with the used gas G1 into a high temperature baking chamber 2, it is oxidized and burned while supplying baking gas G3 such as the air containing much oxygen to make it harmless. The degreased material is moved to a predetermined position in the chamber 2 by a moving member 4 coupled with a driver 11 and primarily baked.