The fabrication of an optical wiring board is performed in the following manner: A core member 13 for a mirror 22 is pattern-formed on a clad layer 11, and simultaneously, using the core member 13, each alignment mark pattern 14 is formed at any position on the clad layer 11. Further, with positioning in reference to each alignment mark 14, the core pattern 13 is subjected to physical cutting to form a bevel part and a concave part 23. Then, a metallic reflective film 18 is coated on the surface of the bevel part. Thereafter, with positioning in reference to each alignment mark 14, an optical wiring core pattern 20 is formed on the clad layer 11 adjacently to the mirror 22.