A very thin flat cable (100) comprising very thin coaxial cables (110) each having a center conductor (1) and a jacket (4), parallel arranged two-dimensionally in a flat shape, and joined by tangling them with a weft yarn (120) in units of predetermined number of very thin coaxial cables (110). The very thin flat cable (100) is characterized in that tangling yarns (130) are parallel arranged along the edges in the width direction of the very thin coaxial cables (110), and the elongation of the weft yarn (120) is higher than that of the tangling yarn (130). When the very thin flat cable (100) is bent, the bent portion of the weft yarn (120)is elongated, and thereby the bent portion of the very thin coaxial cables (110) can escape from the mesh formed by the very thin coaxial cables (110) and the weft yarn (120). Therefore, the very thin flat cable (100) can be freely transformed while maintaining the flat shape and can hold its shape.