A device for the automatic reading of a plurality of codes by means of a key code exceptionally suitable for maintaining a plurality of codes secret and making them available with the introduction of a key code, comprises a plurality of drums adapted to rotate around an axis and a plurality of inserts provided with visible faces suitable for carrying distinctive elements. The inserts are connected in a movable manner along the side edge of each of the said drums to form strings. The drums can be place side by side in an axial direction in order to align all the distinctive elements of a plurality of drums and are inserted on a rod that includes a first stop fixed to one end of the rod itself. A second stop is fixed to the opposite end and locked on the rod.