PURPOSE: To obtain a recording medium exchanger which is merely required to be provided with the moving space for each one piece of respective holders for holding recording media at top and bottom and has the small space by circulating these holders.

CONSTITUTION: Sliders 3 and 6 move toward the left with the same speed when a driving shaft 25 is rotated. Since the right ends of the guide grooves of a chassis extend downward, the shaft 5b of a carrier 5 is lifted to the same height as the height of the shaft 5a and the pawl of the carrier 5 engages with the holder 171. The carrier 1 rises during this time. The carrier 5, thereafter, detains the holder 171 and carries the holder toward the left. A lever 13 is turned when a releasing arm 13c is pressed to the holder 171, by which the engagement with the holders 17A to 17D is released. Further, the carrier 5 pushes up the holders 17A to 17D together with the holder 171 when the sliders 3 and 6 move toward the left. The holder 17B existing in the insertion and expulsion position of the magneto-optical disks move upward and in turn, the holder 17A takes over.