Servo pattern wherein bursts have characteristic phase relationships

In a hard disk, which includes a servo information area where information on the position of a head is recorded and a data information area where actual data information is recorded, the servo information area is divided into an A/B burst section and a C/D burst section, and the A/B burst section has a servo pattern in which phases of burst signals A and B are recorded to be different from each other and the C/D burst section has a servo pattern in which phases of burst signals C and D are recorded to be different from each other. Thus, when the length of a bit recorded on a disk is reduced considerably, an output signal of a head an a burst signal can be detected without distortion and accordingly an accurate control of head tracking is possible.