A turbomolecular pump has rotor blades and at least one pair of electromagnets for levitating the rotor blades and for controlling one of a radial position and an axial position of the rotor. A current supplying device supplies a current to the electromagnets. A detecting device detects a current flowing through the electromagnets. A stopping device stops the supply of current to the electromagnets by the current supplying device when a duration of time during which the current detected by the detecting device exceeds a preselected current value is greater than a preselected duration of time.