PURPOSE: To obtain a plasma processing system having such structure as uniformity can be ensured in the processing by keeping the impedance at power supply section substantially constant regardless of coupling/uncoupling of RF power supply section.

CONSTITUTION: A first RF power supply section 16 having double pipe structure of outside and inside power supply pipes 16A, 16B and connected with the load side, and a second RF power supply section 20 constituted of an outside bracket 22 and an inside power supply pipe 24 and connected with the high frequency power supply side are provided to be coupled or uncoupled each other. At a joint A where the outside power supply pipe 16A and the bracket are fastened through bolts, a conductive ring member 28 is placed between the opposing faces.