A hard disk drive (HDD) having a spindle motor, at least one data storage disk, a disk clamp fastened to the spindle motor and fixing the disk to the spindle motor, and at least one disk spacer mounted on the spindle motor to support the disk. The disk spacer includes a ring-shaped disk spacer body fitted around an outer circumference of the spindle motor with at least one surface contacting the disk, a first groove on the surface of the spacer body contacting the disk, a second groove on the surface of the spacer body contacting the disk to extend along both sides of the first groove, and a damping member between the spacer body and the disk to reduce vibrations of the disk, seated in the first groove in a normal state and compressed by the disk, a portion of which is deformed and accommodated in the second groove.