A method of manufacturing a printed circuit board for optical waveguides, including: preparing a base substrate; forming an optical waveguide, which includes a lower clad, a core formed on an upper middle of the lower clad, and an upper clad formed on the lower clad to surround an upper surface and a side surface of the core, on an upper middle of the base substrate; disposing a side substrate including a first side substrate that has a through hole, through which the optical waveguide penetrates, provided at the middle thereof and a first circuit pattern formed therein and a second side substrate disposed on the first side substrate on the upper part of the base substrate on which the optical waveguide is formed; disposing an upper substrate on the side substrate on which the through hole is formed; and stacking the side substrate and the upper substrate on the base substrate on which the optical waveguide is formed.