To reduce the vibration due to unbalance of the magnetic force generated in a motor part by the vibration of a rotor in a magnetic bearing device having a motor part.

A radial sensor fitted so as to control a magnetic bearing detects the vibration of a rotor. Geometric positional relation between the rotor, the radial sensor and a motor part is utilized so as to estimate the vibration in the motor part on the basis of the vibration of the rotor detected by the radial sensor. The relation between the quantity of the vibration of the rotor in the motor part and the quantity of unbalance of the magnetic force is previously formed into a data base by a test or a simulation, and the quantity of unbalance of the magnetic force is obtained from the data base. The magnetic force resisting the quantity of unbalance of the magnetic force is generated in a coil of a bearing part so as to offset the quantity of unbalance.