The invention provides a plasma processing apparatus in which ring-like conductors 8a and 8b are arranged closed to and along an induction antenna 1 composed of an inner circumference coil 1a and an outer circumference coil 1b. Ring-like conductors 8a and 8b are each characterized in that the radius from the center of the apparatus and the cross-sectional shape of the conductor body varies along the circumferential angle of the coils. Since the mutual inductances between the ring-like conductors 8a and 8b and the induction antenna 1 and between the ring-like conductors 8a and 8b and the plasma along the circumferential position are controlled, it becomes possible to compensate for the coil currents varied along the circumference of the coils of the induction antenna 1, and to improve the non-uniformity in the circumferential direction of the current in the generated plasma.