To provide a holder with an increased number of recording medium disks to be stored in a similar size of a conventional main wall plate as a single holder.

A main frame 1 comprises a peripheral wall 4 standing from a rectangular plane 2 formed on the plane. Holding plates 3 to overlap via gaps of recording medium disks on the plane 2 is rotatably assembled at an end of the main frame 1 inside the peripheral wall 4. In addition, on each of the holding plates 3 and the plane 2 of the main frame 1, spindles 6, 6' for detachably assembling the disks are made to protrude while they are different in position from one another.