Reducing structural vibration is essential for achieving high-accuracy, high-speed head positioning for hard disk drives. In hard disk drives, reaction forces from the head-positioning actuator cause structural excitation in the base. Rotating the carriage by a single-drive actuator also causes structural vibration in the carriage mechanism. Factors contributing to residual vibrations during and after the head positioning have been examined. Based on the results obtained above, measures to reduce residual vibration are proposed.