An apparatus is automatically conveying cartridges reliably and correctly without causing errors, making it possible to enhance the operation efficiency and performance of the apparatus. The apparatus is automatically conveying cartridges disposed adjacent to a recording/reproducing apparatus, and is comprised of a cell mechanism having racks, an accessor mechanism having an accessor, and a conveyance control unit for controlling the conveyance of the cartridges by controlling the accessor mechanism, wherein the accessor is provided with catcher hands, a catcher hand drive mechanism, an open detector mechanism for detecting the open state of said catcher hands, and a closed detector mechanism for detecting the closed state of said catcher hand. The conveyance control unit is equipped with a catcher hand controller which controls the catcher hands to assume an open state, a closed state or a middle state which is an intermediate state relying upon the data detected by the open detector mechanism and the closure detector mechanism.