PURPOSE: To prevent an oven from temperature rising up to the flash point temperature of an oil in a chamber inside even when both of a grill and the oven are simultaneously used by a method wherein the temperature difference between a temperature inside the chamber at the ignition of a grill burner under the minimum throttled condition of an oven burner flame and the maximum temperature under only the ignition of the oven is made as small as possible.

CONSTITUTION: On a back wall 1 in an oven chamber inside, a heat sensing part 2 of a liquid expanding type thermostat is provided on an emission receiving position from an emitting body 4 at the ignition of a grill burner 3. At the simultaneous using both of a grill and an oven, an oven burner 6 secured on a burner supporting plate 5 and provided with a heat shielding plate 7 at the upper part thereof is also ignited. In case of the minimum presetting temperature of a thermostat, the chamber inside temperature becomes T3 under the minimum throttled condition of the oven burner 6 flame. In case of the maximum presetting temperature of the thermostat, the thermostat is acted by the heat sensing part 2 due to the radiated heat from the emitting body 4, then the oven burner 6 flame is minimized, accordingly, the chamber inside temperature becomes as same as T3. At any presetting temperature between the minimum and the maximum temperature, the oven burner 6 flame is throttled at the minimum condition by the same reason, therefore, the chamber inside temperature is kept nearly at constant T3.