To smoothly roll rolling elements (balls) even if the voltage of a voice coil motor is very low.

In this pivot bearing device used for the swing arm support part of a hard disk drive, a cage which has been used to retain the rolling elements 5 at equal intervals is abolished. Since the cage obstructing the operation of the rolling elements when the rolling elements 5 roll is absent, the rolling elements 5 can be smoothly rolled even if the voltage of the voice coil motor is very low.