<p>A plasma processing apparatus M1 is provided with a processing part 20 for supporting a pair of elongate electrodes 30. The processing part 20 is provided with a plurality of pull bolts 52 (approach-deforming preventers) mutually spacedly arranged in the longitudinal direction of the electrode 30. A head part of each pull bolt 52 is hooked on a rigid plate 33 through a bolt holder 53, and a leg part thereof is screwed in the electrode 30. Owing to this arrangement, the electrodes 30 can be prevented from being deformed by Coulomb's force. <IMAGE></p>