is rotated together with the second supporting plate 43 by driving the spindle motor 41 in a state in which the first supporting plate 42 supports the disk 1 also the first 42 and second 43 supporting plates are connected to each other by the pivot pins 45 the pivot pins 45 are for supporting the motion of the pendulums 44 and are installed around the rotating shaft 41 a so that they are parallel to the axial direction x of the rotating shaft 41 a the plurality of pendulums 44 are installed between the first 42 and second 43 supporting plates the pendulums 44 are preferably in the form of plates as shown in fig3 the pendulums 44 in the form of plates are positioned to be parallel to the first 42 and second 43 supporting plates accordingly it is possible to prevent the pendulums 44 from interfering with each other also the pendulums 44 are separated from each other so as not to interfere with each other an end of each of the pendulums 44 is respectively connected to each of the pivot pins 45 by the connectors 46 the connectors 46 preferably comprise string that can be bent even by a very small external force therefore a plurality of strings are connected to the pivot pins 45 and the pendulums 44 also the string is preferably formed of thin iron that has a low stiffness and which is not easy to cut so as to be bent even by the small eccentric mass of the disk 1 as shown in fig4 the pivot pins 45 and the pendulums 44.