mechanical means and then the deposit process is re started arcing may occur thus to damage the substrate if the next deposition process is performed under the state that the electrode contaminated with the solid carbon is not cleaned arcing does not occur initially but arcing occurs after several hours 39 lapse thus disrupting the normal deposition process the problem also arises even when the electrode is formed of tungsten and ar is not used as reaction gas in the present invention if a contaminated portion of the electrode is exposed to the cathode glow or the anode glow for a certain time by performing a discharge using only hydrogen after firstly cleaning the electrode mechanically arcing does not occur during the deposit process thus to implement the same excellent deposition as in the initial condition during the cleaning process the discharge current discharge voltage chamber gas pressure inter electrode distance etc are maintained to be similar to those during the deposition the discharge voltage is automatically controlled according to the discharge current which is lower by approximately 70 u02dc 80v than that during the deposit process during the early part of the cleaning process arcing occurs intermittently and then the number of times that arcing occurs decrease however no arcing occurs after approximately 1 hour after the cleaning process is performed for approximately 1 u02dc 2 hours in a state of no arc occurrence the cleaning process is completed then if the deposit process is re started a stable deposit process with no arcing is obtained in the present invention ar is not used as reaction gas in the conventional art ar is widely used.