A connecting device comprising first and second housing parts which can be rotated in relation to each other, at least one flexible cable element which is arranged between the two housing parts and which can be respectively unwound in a spiral or helical manner with the first and second end section thereof on associated bearing surfaces of the first or second housing part, and a centre section having a U-shaped turning area wherein the winding device is reversed, in addition to means for controlled unwinding of the cable element during winding/unwinding on the bearing surfaces when the two housing parts are rotated in relation to each other. The invention is characterised in that the controlled unwinding means include magnetic and/or magnetizable areas (1a, 1b, 1c) of the cable element (1) and/or housing part which are arranged in such a way that they result in detachable adhesion of the end sections of the cable element (1) to the respective bearing surfaces.