Abstract: The present invention relates to an optosemiconductor device, improved in light-emission efficiency and heat-radiation capability due to its production by molding an anode lead frame and a cathode lead frame with transmission-type epoxy resin and by forming, in the lower end part of the said transmission-type epoxy resin, a layer either of reflective heat-radiating epoxy resin (organic, inorganic, metallic) which contains a heat-radiating filler or of reflective heat-radiating epoxy resin (organic, inorganic, metallic) of mixed hues, along with a method for its manufacture; and by producing this optosemiconductor device by placing such resin as has a filler of a reflective and highly heat-radiating(organic, inorganic, metallic) epoxy resin or reflective heat-radiating(organic, inorganic, metallic) epoxy resin of mixed hues at the lower end of the transmission-type epoxy resin, the present invention is enabled both to prevent the thermal aging inherent in the conventional light-emitting or light-receiving diod