A magnetic bearing device for rotatably supporting a magnetic piece in a levitating state at a specified position comprising: a plurality of electromagnets (2, 3), which are installed opposite to each other, for supporting the magnetic piece, interposed between said plurality of electromagnets (2, 3), in a levitating state by magnetic force; displacement detection means (205, 206, 211) for detecting a displacement of the magnetic piece based on impedance change in the electromagnets (2, 3); and a driver for applying excitation currents (i 1, i 2) to the opposite electromagnets (2, 3) in an alternating manner by controlling switch timing of switching devices (SW 1, SW 2, SW 3, SW 4) so as to support the magnetic piece in the levitating state at a specified position based on a detection signal (V o) from the displacement detection means (205, 206, 211); wherein the driver is a pulse width modulation type driver adapted to control the excitation currents (i 1, i 2) of the electromagnets (2, 3) by modulating a pulse width of a pulse voltage (e 1, e 2) driven at a specified carrier frequency (f c), wherein the excitation current (i 1, i 2) has a direct current component (i c) and an alternating current component (ir 1, ir 2), which is a ripple current generated by the controlling of the pulse width modulation type driver; and wherein the driver includes an alternating current transfer means, the alternating current transfer means being adapted to - when the excitation current (i 1, i 2) flows in one of the electromagnets (2, 3) - allow an alternating current component (ir 2, ir 1) to flow in the other one of the electromagnets (3, 2), but does not allow a direct current component (i c) to flow in the other one of the electromagnets (3, 2), thereby achieving that in operation an alternating current always flows in the opposite electromagnets (2, 3). a plurality of electromagnets (2, 3), which are installed opposite to each other, for supporting the magnetic piece, interposed between said plurality of electromagnets (2, 3), in a levitating state by magnetic force; displacement detection means (205, 206, 211) for detecting a displacement of the magnetic piece based on impedance change in the electromagnets (2, 3); and a driver for applying excitation currents (i 1, i 2) to the opposite electromagnets (2, 3) in an alternating manner by controlling switch timing of switching devices (SW 1, SW 2, SW 3, SW 4) so as to support the magnetic piece in the levitating state at a specified position based on a detection signal (V o) from the displacement detection means (205, 206, 211); wherein the driver is a pulse width modulation type driver adapted to control the excitation currents (i 1, i 2) of the electromagnets (2, 3) by modulating a pulse width of a pulse voltage (e 1, e 2) driven at a specified carrier frequency (f c), wherein the excitation current (i 1, i 2) has a direct current component (i c) and an alternating current component (ir 1, ir 2), which is a ripple current generated by the controlling of the pulse width modulation type driver; and wherein the driver includes an alternating current transfer means, the alternating current transfer means being adapted to - when the excitation current (i 1, i 2) flows in one of the electromagnets (2, 3) - allow an alternating current component (ir 2, ir 1) to flow in the other one of the electromagnets (3, 2), but does not allow a direct current component (i c) to flow in the other one of the electromagnets (3, 2), thereby achieving that in operation an alternating current always flows in the opposite electromagnets (2, 3).