A combined optical and electrical interconnection module includes a flat cable comprising an optical transmission line and an electrical wire, and a printed circuit board including a light receiving module for receiving optical signals and/or a light sending module for sending optical signals and an optical waveguide for the optical signals to be transmitted therethrough or an optical block for bending the optical paths of the optical signals. The printed circuit board is electrically and optically connected to both ends or one end of the flat cable.