PURPOSE: To permit the prevention of the leakage of smoke or smell from the inside of a heating chamber even when a packing, for preventing the leakage of smoke, smell or the like from the inside of the heating chamber, is not attached to a door.

CONSTITUTION: An exhaust fan 12 for sending smoke, discharged out of the exhaust port 9 of a heating chamber 4, to an external exhaust port 2 is provided at the downstream side of the exhaust port 9 while a suction port 19 is formed on the front panel 18 of the heating chamber 4. The suction port 19 is connected to the external exhaust port 2 through a duct 20. On the other hand, a catalyst, adsorbing smoke or smell in the duct 20, is provided in the duct 20 whereby the smoke, discharged out of the external exhaust port 2 through the duct 20, is cleaned.