To improve workability of an assembling process of a disk and a write-in process of servo information by using a disk loading member capable of collectively dealing with plural disks as a disks group.

The disk loading member 20 in the state holding respective disks 2 is attached to a rotary shaft 13. Then, the member 20 is fixed to a rotary shaft binding part 15 by a binding screw 12. The rotary shaft 13 is attached to a fixed pole shaft of a spindle motor mechanism 3. Then, plural disks 2 are collectively dealt with as a disks group by the disk loading member 20 independently of a disk rotation mechanism of an HDD.