HEAD POSITIONING DEVICE, FINE-ADJUSTABLE ACTUATOR DRIVING DEVICE, HEAD POSITIONING CONTROL METHOD, HEAD POSITIONING CONTROL PROGRAM, AND DISK DEVICE

PROBLEM TO BE SOLVED: To realize the high speed and accurate positioning of a magnetic head by preventing piezo-electric elements constituting a fine-adjustable actuator from being shorted due to the precipitation of lead, in a two-stage actuator system. SOLUTION: The head positioning device, which controls the position of the magnetic head 2 for accessing to a magnetic disk 1 with a two-stage actuator system consisting of a coarse-adjustable actuator 51 and a fine-adjustable actuator 52, is provided with a positioning control part 6 for the coarse- adjustable actuator 51 and the fine-adjustable actuator 52 constituted by utilizing piezo-electric elements, and with a fine-adjustable part 64 for driving the fine- adjustable actuator 52 and further with a driving signal limiting means 66 for limiting a driving signal level applied to the fine-adjustable part 64 to a threshold value or below, where a change in the characteristic of the piezo-electric elements is caused.