PURPOSE: To increase the availability factor and work efficiency and enable the regularly stable manufacture of a deposit film of good quality by fastening a rectangular waveguide and a cylindrical cavity resonator so that the axes of them are crossed at right angles.

CONSTITUTION: A cylindrical cavity resonator 22 is fastened so that the rotating axis thereto is crossed at a right angle to the central axis of a rectangular waveguide, converting the TE10 mode of the rectangular waveguide 22 to the TM01 mode of a circular waveguide. The resonator 22 is combined integrally with each matching circuit of a cavity resonator length variable plunger 23 and a cylindrical face slide type diaphragm 24. The diaphragm 24 is disposed in pairs right and left of the crossing part of the waveguide 21 and the resonator 22 right and left, and moves in the longitudinal direction of the waveguide 21. A microwave is amplified within the resonator 22 through the waveguide 21, and the hydrogen gas introduced within a bell jar 25 through a pipe 30 forms the microwave plasma.