PURPOSE: To prevent oily substances dispersed from a cooked item from adhering to a surface of the glass at a cooking housing.

CONSTITUTION: A blowing hole 6 through which hot air generated at a combustion part 2 is blown into a cooking housing 1 is arranged near a door 10, at least a part of hot air blown form it is further blown toward a direction along the inner surface of the door 10 to form an air curtain-like hot air layer at the inner surface of the door 10. The smoke containing the oily component is prevented being adhered directly to the inner surface of the door by the air curtain-like hot air layer and then the condition in which the glass is stained with dirty material to cause the inside part of the cooking housing not to be seen is prevented.