A photointerrupter includes a base, a light emitting element, a light receiving element, a light-transmissive detector resin member covering the light receiving element, a light-transmissive emitter resin member covering the light emitting element, and a light shield layer covering the detector resin member and the emitter resin member. The emitter resin member is spaced apart from the detector resin member with an intervening clearance between them. The detector resin member includes a light incidence surface exposed from the light shield layer, and the emitter resin member includes a light output surface exposed from the light shield layer. The light incidence surface and the light output surface are arranged to face the clearance between the two resin members.