PURPOSE: To obtain a photoelectric type smoke sensor without necessitating the removing work of a smoke sensor and easy to perform maintenance and inspection capable of easily performing not only a performance test but a non- operating test by performing a sensitivity test by currugating a reflecting plate.

CONSTITUTION: First and second reflecting plates 2, 3 a formed in thin pieces in which operating claws 2B, 3B are protruded at sides opposite to that of light reflecting plates 2A, 3A, and their longitudinal sections are formed almost in L-shape. Light absorbing planes 2a, 3a are formed on both upper and lower planes of the light reflecting plates 2A, 3A by coating in black, and light reflecting planes 2b, 3b are formed on the end faces of the light reflecting plate main bodies 2A, 3A by coating in white. The performance test of the sensor can be performed only by erecting the light reflecting plane 2b of the first light reflecting plate 2 without making smoke permit to flow in a smoke sensing room 1, and also, the non-operating test can be performed only by erecting the second light reflecting plate 3. Thereby, it is possible to obtain the photoelectric type smoke sensor capable of easily performing the maintenance and inspection.