Motor vehicle steering shaft and motor vehicle steering system

A motor vehicle steering shaft is provided with: an inner shaft and a tubular outer shaft fitted into each other and to transmit a torque to and from each other; a rigid coupling element for rigidly coupling the inner shaft and the outer shaft in a circumferential direction (C) of the inner shaft when a relative rotation amount of the inner shaft and the outer shaft exceeds a predetermined range; and an elastic coupling element for elastically coupling the inner shaft and the outer shaft in the circumferential direction (C) of the inner shaft when the relative rotation amount of the inner shaft and the outer shaft is within the predetermined range. The elastic coupling element includes a resin member. The inner shaft and the outer shaft are elastically supported mutually via the resin member at a central position of the predetermined range when no torque is loaded to the steering shaft.