Abstract: A bottle stoppering machine includes a travelling belt which carries the bottles to be stoppered, a stopper distributor positioned over the belt, and a stopper driver also positioned over the belt at a position downstream of the distributor. To adjust the vertical separation of the belt and distributor according to undesired variations in the height of the bottles, a first detector detects the approach of a bottle to the distributor, second and third detectors detect excess or deficiency in the height of the approaching bottle, and servo-mechanism controlled by these detectors raises or lowers the belt at the position beneath the distributor, or alternatively raises or lowers the distributor, in response to the signals of the detectors to match the separation of the belt and distributor at the distributor to the height of the bottle to be stoppered.