An optical waveguide device includes a wiring board; an optical waveguide having a first cladding layer, a core layer and a second cladding layer formed in this order on the wiring board; an optical path conversion mirror formed in the core layer; and an optical element mounted on the second cladding layer, the optical element comprising a light emitting portion or a light receiving portion protruding from a lower side thereof. The second cladding layer has an opening formed above the optical path conversion mirror. The optical element is mounted on the second cladding layer so that at least one end thereof is positioned above the opening of the second cladding layer. The light emitting portion or light receiving portion of the optical element is arranged the opening of the second cladding layer.