A method of manufacturing a printed circuit board in which optical waveguides are formed for transmitting optical signals together with electrical signals, which includes a cladding, a core embedded in the cladding that transmits optical signals, and a wiring pattern embedded in the cladding that transmits electrical signals, can offer improved optical connection efficiency and reduced material costs by enabling the cladding to act as an insulation layer and embedding the wiring pattern in the cladding.