A processing apparatus for subject of the present invention uses a high voltage electrode and a ground electrode, and generates plasma under atmospheric pressure in a reaction passage through which a to-be-processed subject passes. For example, even fluorocompound such as PFC including CF.sub.4 can effectively be decomposed because the fluorocompound is brought into contact with plasma in a small space for sufficient time, and the apparatus has a small and simple structure. Therefore, the apparatus can be added to each process chamber.
