The present invention is intended to provide a disk drive apparatus capable of suppressing the occurrence of undesirable vibration due to the imbalance of a disk and capable of carrying out high-rate transfer, wherein a balancer is formed so as to accommodate a predetermined number of spherical bodies in a ring-shaped track portion having a predetermined shape, and this balancer is provided so as to be rotatable integrally and coaxially with the disk. In addition, in the disk drive apparatus of the present invention, the ring-shaped track of the balancer is divided into plural tracks by partition walls or the like, and a ball used as a balance member is disposed so as to be movable on each divided track. Furthermore, the disk drive apparatus of the present invention is configured so that the disk is held on both sides or one side thereof by using four or more projections or rubber sheets.