An optical waveguide device includes a wiring substrate, an optical waveguide bonded on the wiring substrate and having a light path conversion inclined surface on both ends, and a light path conversion mirror formed to contact the light path conversion inclined surface of the optical waveguide and formed of a light reflective resin layer or a metal paste layer. In case the light reflective resin layer is used as the light path conversion mirror, the light reflective resin layer may be formed partially only on the side of the light path conversion inclined surface, or may be formed on the whole of the wiring substrate to coat the optical waveguide.