An evacuation system having a long service life, a compact configuration and high reliability is disclosed. The system enables the process gases to be reused, so that the overall costs of capital investment and operation are reduced. The system comprises a processing chamber, and a vacuum pump communicating with the processing chamber by way of an evacuation conduit for evacuating the processing chamber. The evacuation conduit are provided with not less than two trapping devices arranged in series and operating at different temperatures for capturing different components contained in an exhaust gas discharged from the processing chamber.