An insulator film can be formed at a low temperature without any damage to a substrate to be treated by a plasma in a plasma treatment system which comprises a magnetron for generating a microwave, an isolator for isolating a wave guide from the magnetron, a discharge tube for generating a plasma, the wave guide for leading the microwave from the magnetron to the discharge tube, a vacuum chamber integrally formed together with the discharge tube, an evaporation source provided in the vacuum chamber, a substrate to be treated and provided at a position to sandwich a stream of the plasma between the substrate and the evaporation source, electromagnets provided around the discharge tube and the vacuum chamber, and a manipulator for manipulating the substrate, the electromagnets generating a magnetic field to confine the stream of the plasma.