Abstract: A method of compensating for an imbalance of a hard disk drive includes biasing a plurality of disks in one direction with respect to a rotational shaft of a spindle motor hub, measuring an amount of imbalance of the plurality of disks with respect to the rotational shaft of the spindle motor hub, and compensating the amount of imbalance of the plurality of disks by hitting the hard disk drive in the opposite direction to the one direction in which the plurality of disks are biased to reduce the amount of imbalance with an amount of impact predetermined based on a measured imbalance amount.