There is provided a magnetic disk drive in which a flying-height
fluctuation produced by the operation of a fine actuator is decreased,
the reliability is high, and recording density is high. For this purpose,
the magnetic disk drive is configured as described below. The magnetic
disk drive has a suspension including a base plate connected to a
carriage, a load beam fitted with a slider, and a fine actuator which is
provided on the base plate and finely moves the load beam. The
configuration is such that the shortest track travel time using the fine
actuator is larger than the inverse number of the local maximum of a
flying-height fluctuation frequency of the suspension by the fine
actuator. Also, the configuration is such that the shortest track travel
time using the fine actuator is larger than the inverse number of the
natural frequency of first torsion mode of the suspension by the fine
actuator.