Optical waveguide film, laminated type optical waveguide film, optical waveguide, optical waveguide assembly, optical wiring line, optical/electrical combination substrate and electronic device

An optical waveguide film includes at least one optical waveguide area having an X-direction and a Y-direction orthogonal to the X-direction. Such an optical waveguide film includes a plurality of core portions arranged side by side within the same layer so as to extend along the X-direction, each of the core portions having side surfaces, and the core portions adjoining to each other in the Y-direction being arranged through a gap therebetween; and a plurality of cladding portions provided so as to cover the side surfaces of each of the core portions, each of the cladding portions formed of a resin having an optical refractive index smaller than that of each of the core portions, and the cladding portion between the adjoining core portions providing each gap. In the optical waveguide film, a size of the gap between the adjoining core portions varies along the X-direction in at least a part of the optical waveguide area. This makes it possible to precisely match a gap between core portions in a cut end surface with a desired value by selection of cutting positions of the optical waveguide film even when the optical waveguide film is shrunken.