A buckle apparatus and a seat belt apparatus are provided that are capable of improving the attachment strength of the reflector. In one form, the buckle apparatus includes an upper cover having an insertion inlet at one side, a buckle portion provided in the upper cover and engaged with a tongue of a seat belt inserted through the insertion inlet, a light source provided in the vicinity of the insertion inlet in the upper cover, a reflector for diffusing and leading illuminating light flux eradiated from the light source, which is provided in inner wall faces, that form the insertion inlet by using the reflector as a mold piece.