An object of the present invention is to provide an optical transmission structural body capable of preferably transmitting an optical signal between an optical wiring and an optical waveguide irrespective of a shape of a portion of the optical wiring, the portion being connected to a core part of the optical waveguide.The optical transmission structural body of the present invention is constituted so that at least an optical wiring and an optical waveguide are connected to each other and an optical signal can be transmitted between a core of the optical wiring and a core part of the optical waveguide, wherein a portion of the optical wiring, the portion being connected to the core part of the optical waveguide, is not specially subjected to a planarization processing or has a surface roughness Ra based on JIS B 0601 of 0.1 .mu.m or more.