PURPOSE: To prevent generation of flames in advance by providing a photoelectric sensor in a smoke discharge hood to detect shut-off quantity and inputting a signal into a control means to shut off a fuel shut-off valve.

CONSTITUTION: A photoelectric sensor 15 of transmission type is provided in smoke discharge hood 3 so that signals of said sensor 15 are inputted into a control means 16 to actuate a shut-off valve 6 and an alarm device 17. The sensor 15 consists of a floodlight projector 18 and a light receiver 19 and the projector 18 and the receiver 19 are disposed on the opposite sides of the hood 3 to allow the smoke sucked by an exhaust fan 13 to flow between them. When a large amount of smoke is generated from cooking of tempura and sucked into the hood 3, the light from the projector 18 of the sensor 15 is intercepted and hence the light flowing into the receiver 19 is largely reduced. The sensor 15 detects a decrease in quantities of received light to find out in advance occurrence of a fire of tempura and when the output of the sensor exceeds certain limit, a control means 16 actuates the shut-off valve 6 to cut off supply of fuel and also actuates the alarm device 17. Consequently a fire of tempura can be avoided and safety is improved, without being affected by a cooking apparatus in use.