Abstract: The apparatus comprises an endless tunnel having a wall provided with openings giving access to processing chambers in a locked chamber which has a panel sealing the apparatus from the external environment. A conveyor which follows a closed path is arranged in the tunnel and is provided with seats for containers with articles to be processed and transport means for introducing articles carried by the conveyor into positions opposite to a chamber into a respective chamber. The apparatus has structure by which the environments in the tunnel and in each of the chambers can be controlled. The chambers can each be sealed from the tunnel in a vacuum-tight manner. By means of this apparatus articles, which are screened from the surroundings in a vacuum-tight manner, can be subjected in a controlled environment to a variety of processing steps.