A vaporizer for vacuum deposition installations has at least one crucible and a plurality of crucible-receiving recesses movable into a vaporizing position, a vapor-conducting device and a shutter for interrupting the flow of vapor. The vaporizer is capable of enabling a plurality of different substances to be vaporized in succession without mutual contamination by providing the vapor-conducting device wherein the device has a plurality of vapor screens which can be individually set down at the edges of the crucible-receiving recesses by relative movement between the vapor-conducting device and the crucible. The shutters have a plurality of lobes which can be individually moved over the particular vapor screen located in the vaporizing position. The drives associated with the vapor-conducting device and shutter are interconnected such that the same vapor screen and the same shutter lobe are always associated with a particular crucible-receiving recess.