Abstract: The receptacle includes a lead pin having an optical element, a molded body made of a transparent resin material allowing optical propagation, and an optical element module sub-assembly having a core unitarily molded with the molded body by utilizing a transparent resin material. The receptacle comprises a connector housing unitarily molded with the optical element module sub-assembly by using a transparent material having a refractive index smaller than that of the core. Another receptacle includes an element module sub-assembly which has a lead pin with an optical element and a molded body. The molded body has a recess for positioning a leading end of a ferrule closely to the optical element. The another receptacle also comprises a connector housing having an insertion through hole and an engagement chamber for an optical plug. The optical element module sub-assembly is unitarily assembled with the connector housing.