A photoelectric sensor including at least any one of a light projecting unit for emitting light and a light receiving unit for detecting light includes a substrate on which at least any one of the light projecting unit and the light receiving unit is mounted, a cover which has a protecting portion facing the substrate and for protecting the substrate and a side wall extending from a periphery of the protecting portion, and a sealing member which seals at least any one of the light projecting unit and the light receiving unit that is mounted on the substrate, in which the cover has a protruding portion on a surface which is positioned outside a side surface of the substrate and intersects an extending direction of the side wall, and the protruding portion is in contact with the sealing member.