PURPOSE: To eliminate erroneous lighting-up and manage without setting of the lighting lasting time by using a reflex type photo-electric sensor, and lighting up or putting off if a pulsed photo-signal emitted is in synchronization with the reflex wave signal, which should assumed as a regular sensing signal.

CONSTITUTION: A pulsed photo-signals S0 is emitted from an infrared emitting diode 22 of a light projector 23. If a hand 37 is inserted within the sensing range 38 in such a way as intercepting this signal S0, it is reflected by the hand 37, and a pulsed reflex wave S1 with the same period as S0 is cast into a photo-transistor 24 in a light receiver 25. The output of another light receiver 26 gets rid of foreign noise components while passing through an amplifier 30, sensitivity adjusting part 31, and noise removing part 32, and a lighting circuit 21 is turned on and off through FF circuits 33, 34 and a driving part 35. This eliminates malfunction when a cooking fixture is approached uninten tionally, and allows managing of leaving the kitchen without troublesome opera tion for continuing the lit condition.