Abstract: A magnetic recording and reproducing apparatus having the magnetic disc cassette with a built-in shutter, a shutter lever for opening and closing the shutter and lock lever for controlling a lowering and raising of a holder are installed on an upper surface of the holder. During the insertion of the magnetic disc cassette, the shutter lever releases the shutter, the lock lever is disengaged from a locking step of an eject lever, the shutter lever is lowered into the cassette and releases the shutter, and a magnetic head contacts the magnetic disc. During ejection of the cassette, a lock releasing step of the eject lever is pressed on a stop lever, the stop lever is rotated and is disengaged from the lock lever, an operation lever of the lock lever is disengaged from the shutter lever, and the cassette is disengaged and simultaneously the shutter is closed.