PURPOSE: To apply the energizing force of an elastic member in the reverse direction to a vibration direction to restrain the vibration of a disk plate by arranging a weight, movable in the axial direction of the disk pate, via an elastic member in the inside of the disk plate to be braked by the pressing of a friction pad from both sides.

CONSTITUTION: In a disk plate 3 to be braked by the pressing of a friction pad from both sides, two disk parts 9 are lined by plural linking parts 10, and also plural ventilation spaces 11 are defined between both the disk parts 9. At that time, plural dynamic vibration reducers 12a (12a) are arranged in the given ventilation spaces 11. When the disk plate 3 is vibrated in an axial direction, force is generated by the dynamic vibration reducer 12a in the reverse direction to this vibration direction. That is, a weight 15, movably inserted via a through-hole 14 into a guide rod 13 mounted between both the disk parts 9, is stopped by inertia, and also energizing force following telescopic motion is generated in spring 16 interposed between both the disk parts 9 and the weight 15. Consequently the engaging force can be applied in the reverse direction to the vibration direction.