an adjusting device for adjusting the wear of the friction surface on the brake lining and brake disc of a pneumatic disc brake having a clamping device that is actuated by a rotary lever is provided . the device preferably can be inserted into a rotary spindle of the disc brake . an anti - friction body is positioned on both axial sides of a drive element , with the one bodies being a ramp coupling with a freewheeling function . the ramp coupling has coupling bushes and clamping balls , and the coupling bush on the driven side being supported on a spring sleeve . a conical seat is configured between the coupling bush and the sprung sleeve cooperates with the ramp coupling to preclude locking of the coupling bushes .