NOVELTY - Providing processing apparatus of halogen containing gas.    USE - For exhaust gas containing carbon tetra fluoride, semiconductor device or liquid crystal display device forming process.    ADVANTAGE - The processing apparatus is inexpensive and processes reduced concentration gas with plasma efficiently and easily without using high energy and irrespective of dilution concentration. The influence on global warming is prevented. Excessive additional gas introduced by discharge portion is prevented and hence stable discharge is maintained. Supply of purge gas is reduced and corrosion of piping by the discharge gas is prevented by using non-halogen containing gas. Hence the corrosion resistance of the processing apparatus, stability, life span, insulation and emission characteristics of the discharge portion are improved. The processing apparatus absorbs mechanical or thermal stress produced inside the unit. Discharge void length is improved and hence stable operation is realized even at high temperature in discharge space. The running cost is reduced and absorbent, disturbance gas in the halogen containing gas are removed.    DETAILED DESCRIPTION - The processing apparatus of halogen containing gas comprises a cooling unit to cool discharge portion (33), ground-contact lateral electrode (331) and high-voltage lateral electrode (332) arranged oppositely through the dielectric provided to at least one surface. High voltage is impressed to the discharge portion and the discharge is generated. The processing apparatus decomposes halogen containing gas supplied by the halogen containing gas supply unit between the two electrodes. The gas pressure in the discharge space between the two electrodes is atmospheric pressure or a pressure near atmospheric pressure. When one electrode is cooled, the discharge void length of the discharge space is set to 1 mm or less. When both the electrodes are cooled, the discharge void length of the discharge space is set to 4 mm or less.    DESCRIPTION OF DRAWING(S) - The figure shows the sectional drawing showing the discharge portion of the processing apparatus. (Drawing includes non-English language text).    Discharge portion (33)    Ground-contact lateral electrode (331)    High-voltage lateral electrode (332)    Discharge space (333)    Spacer (334)