An object of the invention is to provide a disc autochanger without any disc reversing mechanism by using on A-side recording and reproducing apparatus and a B-side recording and reproducing apparatus while using a sheet-like optical disc in which both surfaces can be recorded and reproduced. The disc autochanger is constituted by a cartridge storing a plurality of sheet-like optical discs in which both surfaces are recorded and reproduced in a state of putting in a tray, the A-side recording and reproducing apparatus in which a moving table of an A-side recording and reproducing portion is arranged in an upper side of a tray take-out mechanism and a moving table of a cap is provided in a lower side thereof, and the B-side recording and reproducing apparatus in which a moving table of a B-side recording and reproducing portion is arranged in a lower side of the tray take-out mechanism and a moving table of a cap is provided in an upper side thereof. Accordingly, since it is possible to alternately supply the sheet-like optical discs in which both surfaces are recorded and reproduced to the A-side and B-side recording and reproducing apparatuses from the cartridge, it is possible to record and reproduce continuously and in parallel.