A torsional vibration damper includes a primary mass defining a ring-shaped chamber, a secondary mass relatively rotatably connected to the primary mass, and a damping unit for coupling the primary and secondary masses to each other in a rotationally elastic manner. The damping unit comprises a plurality of coil springs, a pair of end guides, and a friction member slidably disposed between neighboring coil springs. The friction member is configured to be rubbed against at least one of an inner wall and an outer wall of the ring-shaped chamber in response to compressions of the coil springs such that a friction force is generated in proportion to a relative rotation between the primary and secondary masses as well as to a rotational speed thereof.