To make a rotation machine possible to stably rotate in the number of revolutions in a wide range by suppressing the vibration of the rotation shaft of the rotation machine.

The shaft 3 of the rotation machine is supported by a second yoke 102, electromagnets (101, LYa, etc.) is arranged corresponding to this second yoke 102 and the displacement of the second yoke 102 in a direction crossing the shaft 3 is detected by a distance sensor 103Y. Then based on a detection signal obtained from this sensor, a magnetic force generated by the magnet is controlled to vary the spring constant of an elastic body 104 to suppress the vibration of the shaft 3 across a wide band through the second yoke.