PURPOSE: To reduce the lengths of used flat cable and dummy cable compared with conventional ones.

CONSTITUTION: Respective necessary numbers of flat cables 6 and dummy cables 7 having the spring property substantially equal to the flat cable 6 are wound in the state where the winding direction is reversed in the middle of the longitudinal direction, and housed in an annular space formed by an inner circumferential-side case 5 and an outer circumferential-side case 8 which are relatively rotatable and concentrically combined together. In a transmitting device between rotor and fixed body in which one-side ends 6b, 7b of these flat cables 6 and dummy cables 7 are fixed to the inner circumferential-side case 5, and the other ends 6c, 7c to the outer circumferential-side case 8, W the width of the dummy cable 7 is set smaller than the width of the flat cable 6, and a plurality of dummy cables 7 are arranged in parallel in the width direction, and wound together with the flat cables 6.