A clamping device (1) of a traction mechanism drive, comprising a fixedly positioned base part (2), with which a pivot arm (3) is associated. The pivot arm (3) can be pivoted via a rotary bearing, consisting of a hub (9), a pin (5) of the base part (2) and a sliding bearing (10). A spring means (12) inserted between the base part (2) and the pivot arm (3) exerts an expansion force and effects a non-positive support of a tensioning roller (11) that is connected to the pivot arm (3) on a traction mechanism. In order to damp adjusting movements of the pivot arm (3), a damping device (13) is provided, which comprises two separate spring-loaded friction elements. For this purpose, a friction disk (14) is supported with form fit on the supporting disk (8) connected to the pin (5) of the base part (2) and with friction fit on the pivot arm (3). The damping device (13) further comprises a friction ring (17), which is fixed to the pivot arm (3) and is supported with friction fit on an inner wall (19) of the crucible-shaped base part (2) and which directly cooperates with the spring means (12).