To substantially reduce the volume of a radiated sound so as to provide good silence by providing a non-flat radiated sound dispersing part in the end surface part of a mass body in an axial direction in a damper where the mass body is connected to a hub via an elastic body made of a rubber elastic material.

In a torsion damper where a hub 1 and a mass body 4 are made of metal such as cast iron to be annular and the mass body (vibration ring) 4 is connected to the outer peripheral side of the cylindrical part 1a of the hub 1 via a sleeve 2 and an elastic body 3, a radiated sound dispersing part 5 protruded in a roughly circular-arc sectional shape is integrally formed to be annular in the axial direction end surface part 4a of the front side of the mass body 4. The axial direction end surface 4b of the mass boy 4 in an engine side is formed to be flat orthogonal to the center axis O of the damper. Since the radiated sound dispersing part 5 is integrally formed in such a manner, the direction of a sound radiated from the radiated sound dispersing part 5 is dispersed or diffused and thus the volume of the radiated sound is substantially reduced.