A servo writing device which writes servo data in each sector of each track of
a magnetic disk, wherein servo data recorded positions of the tracks are mutually
corresponded. The servo writing device includes a clock head for generating reference
clock signals and a standard clock generating circuit generating standard clock
signals, whose frequency is higher than that of the reference clock signals and
which is not synchronized with the reference clock signals. The device further
includes a start pulse generating circuit receiving the reference clock signals
as clock signals and generating a start pulse corresponding to the servo data recorded
position and a synchronizing circuit synchronizing the start pulse with the standard
clock signals and generating a synchronizing-start pulse. In addition, the device
also includes a pattern generating circuit receiving the standard clock signals
as clock signals and generating the servo data synchronizing with the synchronizing-start pulse.
