a magnetic bearing device has a rotor , electromagnets that control axial / radial positions of the rotor , and a power source that supplies power to the electromagnets . a switching circuit switches a voltage of a common node connected to each one end of the electromagnets . the switching circuit includes a first switch element that connects and disconnects between one end of the power source and the common node , and a first rectifier element connected between the other end of the power source and the common node . an excitation control circuit controls excitation of each of the electromagnets by a supply current that flows through the electromagnets in one direction or a regenerated current that flows through the electromagnets in one direction . the excitation control circuit includes a second switch element that connects and disconnects between the other end of one of the electromagnets and the other end of the power source , and a second rectifier element connected between the other end of one of the electromagnets and the one end of the power source .