Abstract: A disc drive particularly adapted to perform recording and/or reproducing operation with respect to a disc cartridge containing a magneto optical disc is composed of a main chassis for mounting thereon a pick-up mechanism, a loading chassis for accommodating the disc cartridge and vertically shiftable between its lower operative position and upper retracted position, a bias magnet mounted on the loading chassis for applying a magnetic field to the disc when the loading chassis is in the lower operative position, and a sliding plate slidably arranged on the main chassis for shifting the loading chassis between two positions along with sliding movement thereof. The bias magnet is shiftable substantially in a vertical direction with respect to the loading chassis and therefore separatable from the latter when the latter is in the upper retracted position for allowing smooth insertion of the disc cartridge.