Abstract: A hub holder which pushes the center hub of a magnetic disc to a reference surface for setting is associated with a cassette guide for guiding a magnetic disc cassette to a recording/reproducing position at which information is recorded or reproduced to or from the magnetic disc, so that the hub holder's displacement can be amplified by a required degree. An upper dust-proof door and a lower dust-proof door are swingably disposed at the cassette insertion opening of a magnetic disc unit, and they are normally so biased that they close the cassette insertion opening dust-tightly. When they are closed, one of them abuts against the other. Thus, the magnetic disc unit is compact in size and light in weight, easily clamps the center hub of the magnetic disc, and is closed in a completely dust tight manner.

Abstract: A recording-reproducing apparatus, comprising first and second holding members and support member for supporting said first and second holding members, and for permitting said first holding member to move towards and away from said second holding member. The first holding member holds on one side thereof, a container member for containing a recording medium therein, and on an opposite side thereof, an adjusting member for adjusting the position of the recording medium. The second holding member holds a driving member for driving the recording medium.