Disk writer and writing method thereof

The present invention, as in the disc constituting the HDD on the disc recording apparatus for recording servo data, and a reference signal writer to record the reference signal in accordance with a predetermined distance from the track from the edge of said disk on said disk .; Characterized by a servo writer having a recording unit for recording servo data on the disk, and a detector for detecting a reference signal recorded on the disc, the detected point of the reference signal as a reference. In this way, it is possible to minimize the position error of the start track, it is possible to reduce the defect of the HDD.