A method of manufacturing an optical waveguide device is provided which provides the excellent smoothness of a light receiving end surface and a light emitting end surface formed by cutting and which provides excellent productivity. A laminate of a film element (2) and a board (1) is prepared. The film element (2) includes at least one future optical waveguide portion. The board (1) is stacked on the film element (2). The laminate is die-cut from the side of the board (1). This provides an optical waveguide device including the die-cut board (1) and an optical waveguide formed thereon. A cutting die used for the die-cutting includes at least blades (3) for forming the light receiving end surface (20a) and the light emitting end surface (20b) of the optical waveguide. The blades (3) are flat blades including blade surfaces having an arithmetic means roughness (Ra) of less than 0.02 μm.