Limited area reflective photoelectric sensor

PROBLEM TO BE SOLVED: To provide a limited area reflection type photoelectric sensor that can accurately detect an object in which a distance to a measured surface varies by broadening a detection range, and has a simple configuration.SOLUTION: A limited area reflection type photoelectric sensor 1A comprises: a light projection part 10 that has a laser diode 11; and a light reception part 20 that has a photo diode 21. The light projection part 10 and the light reception part 20 irradiate object detection limited areas S1 to S3 with a light projection beam from the light projection part 10, and an angle of an intersection where an optical axis of the light projection beam and an optical axis of a light reception beam go across each other is set so that a light reception beam of reflection light from an object M existing in the object detection limited areas S1 to S3 can be received by the light reception part 20. Whether the object M exists is determined on the basis of a level of the light reception on the photo diode 21. On an optical path of the light projection beam from the laser diode 11, a diffraction grating 13 is provided that divides the light projection beam into beams in a plurality of directions.