This application discloses an insulation-film etching system that etches an insulator film on a substrate by a species produced in plasma. The apparatus comprises a process chamber in which the etching process is carried out, a substrate holder that is provided in the process chamber and holds the substrate, a gas introduction line to introduce a gas having an etching function into the process chamber, a plasma generator to generate the plasma of the introduced gas, and a transfer mechanism to transfer the substrate into the process chamber and to transfer the substrate out of the process chamber. The gas introduction line is capable of introducing a gas having a cleaning function to remove a deposited film on an exposed surface in the process chamber, instead of the gas for the etching. The system comprises a control unit that carries out the sequence control. According as the sequence control, the cleaning is carried out after the etching.