Provided is a photoelectric sensor that enables manufacturing of a sensor with high environmental durability in a case in which there is more variation in case bodies. A photoelectric sensor includes: a package that includes an optical unit and a sealing member that seals the optical unit, and the optical unit includes at least any one of a light projecting portion that emits light and a light receiving portion that detects light; and a case body that accommodates the package, and a gap is provided between the package and the case body.