A flat cable including thin coaxial cables each having a center conductor and a jacket, parallel arranged two-dimensionally in a flat shape, and joined by tangling them with a weft yarn in units of predetermined number of very thin coaxial cables. The flat cable further includes tangling yarns that are arranged parallel along the edges in the width direction of the thin coaxial cables, and the elongation of the weft yarn is greater than that of the tangling yarn. When the very thin flat cable is bent, the bent portion of the weft yarn is elongated, and thereby the bent portion of the very thin coaxial cables can deviate from the mesh formed by the very thin coaxial cables and the weft yarn.