SMOKING SENSOR

PROBLEM TO BE SOLVED: To prevent interference in sensing smoking in a smoking sensor. SOLUTION: This smoking sensor 1 provided with a smoking sensor 13 for detecting infrared rays, is provided with a distance sensor 16 for detecting an act of interference in sensing smoking, and a loudspeaker 20 for outputting an alarm in either case of detecting the interference or sensing smoking. The distance sensor 16 is an infrared reflection type distance measuring sensor for measuring the distance to a measured object to detect the measured object to be in a prescribed range by emitting infrared rays and receiving reflected light from the measured object. The smoking sensor 13 is provided with a quartz filter 14 for selectively transmitting infrared rays emitted from the light of a cigarette and the flame of a lighter and cutting off infrared rays emitted from a human body, and a sensor cap 15 whose head part 15b is a Fresnel lens.