PURPOSE: To prevent the flexure of a rigid shaft without enlarging diameters of the rigid shaft, a rotor and a device by a construction in which the free end side of the rigid shaft is extended in the direction of a spindle for supporting by the spindle, and the rigid shaft is supported by a bearing flange and the spindle at both ends.

CONSTITUTION: A recess 101 having a circular cross section is formed on a spindle 6' side. The free end 1a of a rigid shaft section 1 is extended and is fitted to the inside of the recess 101 in a state to provide gaps in the direction of the shaft and in the direction of the diameter. According to the constitution, the flexure of the rigid shaft 1 can be prevented without enlarging diameters of the rigid shaft 1, a rotor and a device.