The photoelectric sensor includes a light projecting part emitting light, a light receiving part receiving light, a housing housing the light projecting part and the light receiving part, a setting part receiving an input operation from outside to set a threshold value, and an adjustment part receiving an input operation from outside to finely adjust the set threshold value. The housing includes a front surface having a light projecting/receiving surface allowing light from the light projecting part and light to the light receiving part to pass, a rear surface located on a side opposite to the front surface, a top surface adjacent to the front surface and extending in a direction orthogonal to the front surface and the rear surface, and an inclined surface inclined with respect to and connecting the top surface and the rear surface. The adjustment part is provided on the inclined surface.