In an air lock for continuous introduction into and/or removal of workpieces from spaces (1, 4) separated atmospherically, the individual substrates (3, 13) are transported through a transfer channel (24). At least one lock chamber (7a-7m) serving to accommodate the substrates (3, 13) is arranged movably in the transfer channel (24). During the substrate transport in the transfer channel (24), the lock chamber (7a-7m) is atmospherically separated both from the exterior (1) having normal pressure and from the coating chamber (4). The air lock (2) includes a carrousel lock which has a carrousel housing (24) and a lock chamber wheel (10). On the periphery in the lock chamber wheel (10) individual lock chambers (7a-7m) are provided, in which the workpieces (3, 13) to be brought into the chamber to be loaded (4) are inserted freely accessible on the normal pressure side. By turning the lock chamber wheel (10), the substrates (3, 13) in the lock chambers (7a-7m) are transported from the coating station [sic; loading station] (A) to the transfer station (B) into the treatment chamber (4) diametrically opposite the normal pressure side. In the transfer station (B) the substrates (3, 13) are removed from the transfer channels (7a-7m) by means of a transfer device (17′) and are available for further treatment in the treatment chamber (4).