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.