To refine on an apparatus as a rotor shaft of an open-end spinning apparatus which supports a spinning rotor in a wedge-type supporting space of a bearing mechanism for supporting disks and positions it with a magnetic thrust bearing.

The magnetic thrust bearing 18 of this invention has (A) a stationary bearing component 41 having permanent magnet members placed among magnetic pole disks 46... and (B) bearing components exchangeably and rotatably placed along with a spinning rotor. The rotatable bearing components are composed of ferromagnetic ring-adding parts placed in a rotor shaft 4. The rotor shaft 4 has a bearing part in an end side in which the diameter of the shaft 4 is reduced, and is provided with at least three ferromagnetic ring-adding parts 32, 33, 34 each placed at the interval of the magnetic pole disk 46.... A structure and an arrangement of the parts 32, 33, 34 are rationalized according to rightful services.