PURPOSE: To prevent the intrusion of dust into a magnetic disc unit through a shield cover while facilitating adjustment of clearance between a disc cartridge and spacers on 0 side and 1 side.

CONSTITUTION: Clearance between a 0 side spacer 31 and a disc cartridge 3 can be adjusted by means of an adjusting screw 34 through a leaf spring 32 fixed to the frame 4. Furthermore, a 1 side spacer 35 is secured through a screw to a cartridge holder 2 and the clearance between the 1 side spacer 35 and the disc cartridge 3 is adjusted by means of an adjusting screw 37 provided in the 1 side spacer 35.