Abstract: An unstacking apparatus including a first suction nozzle (7) and a second suction nozzle (8) that are disposed on one side of an alignment plate (3), a perforated endless belt (6) continuously advancing past the suction nozzles and the free face of the first item in a stack of items, a passage forming an outlet between the alignment plate and the belt, at least one sensor (17, 18, 19) disposed on the other side of the alignment plate, and a microcomputer (10) for actuating one of the nozzles in an unstacking cycle. A microcomputer is organized so as to detect that a first item in the stack is backwardly misaligned by monitoring the operation of one of the suction nozzles during the unstacking cycle, and so as to trigger a realignment cycle in response to such detection, during which realignment cycle the nozzles are actuated alternately.