A flexible optical waveguide film comprises: two waveguide cores; and a clad surrounding the two waveguide core, wherein a light entrance/exit part is disposed at one end of each of the two waveguide cores, the waveguide film having an optical path converting part comprising an air void located inside the waveguide film, and a light entrance/exit end face of the light entrance/exit part is a plane surface facing an optical path converting surface of the optical path converting part, the optical path converting surface being an interface defining the air void.