A disk holder for an off-line servo-track writer is installed at a driving motor of the off-line servo-track writer in a state in which a plurality of disks for information storage are assembled to the disk holder. The disk holder has a flange for supporting the plurality of disks, a mounting portion to be joined to the driving motor is provided at one side of the flange, and a hub is provided at the other side of the flange. A space into which air flows is formed in the hub, and the plurality of disks and a plurality of spacers for maintaining a gap between the plurality of disks are assembled around the outer circumference of the hub. A plurality of pressing members are installed at the hub to move back and forth in a radial direction of the hub.