Abstract: A process of forming a film on a substrate, which comprises bringing a substrate into contact with a plasma zone formed by generating, by use of a discharge electrode or discharge electrodes, high temperature or quasi-high temperature plasma of a gas containing at least one carbon containing compound,wherein said electrode comprises a sheet-like electrode provided with a slit having a linear portion and connected to a microwave electric source; orwherein said plasma zone is formed by forcing a high temperature or quasi-high temperature plasma generated in an arc between said electrodes by DC discharge, to move by applying a magnetic field. The process enables formation of films on substrate surfaces in a high energy efficiency.