A medium stocking apparatus includes a housing having an open area, reels on which tapes are wound, a diverting unit for turning backward the tapes, a cylindrical drum on which a medium is wound with the tapes overlaid, and an openable unit for closing and opening an internal space from and to outside. During an operation, a closed state can be retained, and, during a maintenance work, an open state can be achieved, in which the openable unit is rotated in an upward direction for displacing upper tapes. The medium stocking apparatus can thus be offered which allows a maintenance work with high workability without impairing the tapes.