The rolling bearing apparatus of the present invention comprises a rolling
element, a non-rolling element disposed concentrically with the rolling
element, and a rotation detector for outputting an input exciting voltage
by converting it to an induced voltage according to the relative rotation
state of the rolling element and the non-rolling element. The rotation
detector comprises a rotor provided in the rolling element, a stator
provided in the non-rolling element, and an exciting winding and output
windings being wound to the stator. The output windings induce a voltage
according to the gap permeance between the rotor and the stator in
response to the exciting voltage inputted to the exciting winding.