An anchoring element for fastening a rod of a device for adjusting a human vertebral column on a vertebra and having a retainer for receiving the rod, a securing element attachable on the retainer and acting against the rod, a fastening element for attachment to the vertebral body and a clamping device between the retainer and the fastening element including a ring-shaped mount, a partially spherical bearing and an intermediate element embedded in the mount and surrounding the bearing. The bearing comprises level guiding surfaces on opposite sides. The intermediate element has mating counter surfaces which enable the retainer to move in one axial direction only relative to the fastening element and the level counter surfaces are formed on an inner side of one of two generally circumferentially extending elongate segments of the intermediate element.