The clamping device according to the invention for clamping at least two processing devices for a sample preparation is made up essentially of at least three clamping blocks arranged in the axial direction, at least two of which are designed as movable clamping blocks, and a displacement mechanism for displacing the movable clamping blocks between an open position for inserting the processing devices, and a clamping position in which the at least two processing devices are clamped one on top of the other in the axial direction between two clamping blocks in each case. The displacement mechanism is designed for displacing the at least two movable clamping blocks in opposite directions.