To provide a magnetic bearing device suppressing rigidity lowering of a rotor shaft as much as possible, simultaneously detecting displacement with high precision, stably controlling and supporting a high-speed rotator.

A rotor section of the magnetic bearing 12 is comprised of a solid rotor 11 of magnetic material and a sensor for detecting displacement of the rotor section is comprised of an eddy current sensor 15. A sensor target 15b of the eddy current sensor 15 is formed of a nonmagnetic material ring and installed on an outer periphery of the solid rotor 11. With this construction, the solid rotor 11 suppresses lowering of the shaft rigidity as much as possible and the sensor target 15b formed of the nonmagnetic material ring blocks off leakage flux of an electromagnet of the magnetic bearing 12 and influence of an eddy current caused by it so that displacement can be detected with high precision and the high-speed rotator can be stably controlled and supported.