A sealing element for rotatable parts is provided by the invention. To achieve low and uniform wear, automatic reshaping of the sealing surfaces for advancing wear, low friction forces, and long service life, the sealing element has sealing surfaces (4) and sealing counter surfaces (5), whose sealing effect is provided by the interaction of a sealing element (3, 11) constructed as a tractrix body with a correspondingly shaped sealing counter element (6, 13, 14).