PURPOSE: To reduce the torque variation and noise by connecting one edge part of a frictional member with one between a revolution member and a driven member, allowing the outer edge part to be attached to the other by a prescribed pushing force, ad generating elasticity in the circumferertial direction.

CONSTITUTION: When the load torque applied on a driving shaft 2 varies, the variation is transmitted to an electromagnetic clutch 1 side from a driving shaft 2, and accompanied with the elastic deformation in the revolution direction of a rubber hub 15, if a relative revolution is generated between an outer hub 13 and an inner hub 14, a contact 7b does not slidingly move for the outer hub 13, since the repulsive force generated in the contact part 7b of a frictional plate 7 is small in the range having a small relative angular displacement, and the resonance point of the torque variation shifts to the high frequency region in comparison with the case consisting of only the rubber hub 15. When the frequency of the torque variation increases to increase the torque amplitude, and the relative angular displacement between the outer hub 13 and inner hub 14 increases, the frictional sliding between contact part 7b and the outer hub 13 is eliminated, and the vibration energy is absorbed, and converted to the heat generation energy, and the torque variation is reduced.