PURPOSE: To miniaturize a rotary vibration-controller and improve its controllability by arranging a yoke inside a housing, winding a coil on the yoke, installing permanent magnets, and fixing a rotor on a ball nut which is installed through a linear guide.

CONSTITUTION: A pair of metal fittings 15 and 15 are connected with a movable side member and a fixed side member, and if the vibration, etc., in the lateral direction are applied between an arm 7 and a stay pipe 6, a shaft 8 is revolved through the screwing between a ball nut 10 and a ball screw 8a. Accordingly, also a holding member 13 fixed on the shaft 8 revolves, and a rotor 14 revolves in a cavity 5 formed between permanent magnets 4 and 4. Further, since the rotor 14 is made of the electric conductive material, an eddy current is generated by the revolution inside the rotor 14. The magnetic field induced by the eddy current acts in the reverse direction to the magnetic field by the permanent magnet 4, a brake action is generated for the rotor 14. Further, the hysteresis loss acts as the brake power for the rotor 14.