The apparatus has a processing chamber in which a workpiece is processed with a processing tool. Additionally an introducing device is provided as part of the processing chamber wall, being disposed such that a closed space is formed at least during processing of the workpiece in the processing chamber. Additionally one disposes on the introducing device at least one workpiece holder that is rotatable by a drive about a rotation axis in the workpiece plane and is moved in or out of the processing chamber by the introducing device.