A light emitting device and a light receiving device are in a bare chip form and are a light emitting device of surface emitting type and a light receiving device of surface receiving type having an electrode on an opposite surface of a light emitting portion and a light receiving portion respectively, the light emitting device, the light receiving device, and an optical waveguide are mounted on one surface of a flexible printed wiring board body, the light emitting portion of the light emitting device, an optical waveguide core, and the light receiving portion of the light receiving device are arranged substantially coaxially, and the light emitting device and the light receiving device are mounted in such a way that a light emitting/receiving direction is substantially 90° with respect to an orthogonal direction of a surface of the flexible printed wiring board body.