A photoelectric sensor includes a connecting section for light projection to which a light propagation member for light projection optically coupled to a light emitting element is connected, a connecting section for light reception to which a light propagation member for light reception optically coupled to the light receiving element is connected, a signal generating unit configured to compare a light reception signal generated by the light receiving element and a threshold and generate a detection signal indicating a result of the comparison, a first light emitting element for indication optically coupled to the connecting section for light reception, and a mounting substrate on which each of the first light emitting element for indication and the light receiving element is positioned in the connecting section for light reception or one of the first light emitting element for indication and the light receiving element is positioned via the other.