Abstract: A disk holder according to the present invention has a first core 1 and a second core 2. The cores are members having a given length with a generally U-shaped cross section and combined to oppose to each other so that adjustment of expansion and contraction of the cores can be carried out between an expanded diameter position and a contracted diameter position. The surfaces of the cores 1 and 2 are provided with rows of guides 7a and 7b and supports 8a and 8b. The row of the guides 7a and 7b forms flutes for receiving disks D one by one inbetween the guides to hold the disks at predetermined intervals. The supports 8a and 8b are projected rows for supporting the inner periphery of the axle hole of the disk by three-point support, the supports 8b being provided with resiliency. The holder 5 is inserted into the axle hole of the disk D at the contracted diameter position and supports a plurality of disks D, D, D . . . in a row at the expanded diameter position.