PURPOSE: To link the light guide and the optical fiber through the optical film semipermanently by forming the optical film at the prescribed edge surface of the substrate in the light guide, after the optical film and the light guide edge are unified, melting and unifying the edge part of the optical fiber at the optical film.

CONSTITUTION: First, a prescribed edge surface 2a of a substrate 2 s optically ground, at the edge surface 2a after grinding, an optical film 4 composed of SiO2 through the glass evaporating means such as the sputter method is formed, and the edge part of a wave guide part 3 is unified with the optical film 4. Next, the edge part of an optical fiber 5 is abutted to the optical film 4, heated by the arc discharging, etc., and the edge part of the optical fiber 5 is adhered to the optical film 4 by fusion. Thus, the connecting part of a connected light guide 1 and the optical fiber 5 has the tensile strength equal to the case when the optical fiber is mutually adhered by fusion and connected, and for a long time, the dislocation will not occur at the light axis of the light guide path 1 and the optical fiber 5.