To provide a magnetic bearing device, and a pump unit mounting the magnetic bearing device, in which position control to a rotary body is performed at high speed and with strong force, and in which vibration generated from the pump unit can be reduced, and electric/magnetic noise generated from the pump device is reduced.

An electromagnetic winding 151 is changeable to a high voltage mode in which power is fed from a high voltage power source 171 and a low voltage mode in which power is fed from a low voltage power source 271. This change is determined based on if current change speed diL/dt is reference current change speed diLs/dt or over or not. When it is the reference current change speed diLs/dt or over, it is changed to the high voltage mode. When it is less than the reference current change speed diLs/dt, it is changed to the low voltage mode.