A method of manufacturing an opto-electric hybrid board which is capable of reducing the number of steps for the manufacture of the opto-electric hybrid board and which achieves the reduction in thickness of the opto-electric hybrid board to be manufactured, and an opto-electric hybrid board obtained thereby. A plurality of protruding cores (optical interconnect lines) 3 are formed in a predetermined pattern. Thereafter, a thin metal film 4 is formed in grooves defined between adjacent ones of the cores 3. Via-filling plating is performed on the thin metal film 4 to fill the above-mentioned grooves with a via-filling plated layer 6a. The plated layer 6a serves as electrical interconnect lines 6.