A photoelectric sensor includes: a light projecting section projecting detection medium light to a detection object region; and a light receiving section receiving reflecting light or transmitted light from the detection object region, the sections being in a single piece or in separate pieces. The light projecting section includes: a light source generating the detection medium light; and a light projecting lens for collimating or collecting the detection medium light from the light source to form a beam spot or a light collecting point in the detection object region. The light projecting section further includes: a deflection angle adjusting unit capable of finely adjusting an optical axis deflection angle of the detection medium light projected to the detection object region from the light projecting section.