To prevent an organic halogen compound discharge decomposition apparatus preventing vibration of a discharge tube.

The organic halogen compound discharge decomposition apparatus is provided with a discharge tube 4 in which a gas containing the organic halogen compound flows and thermal plasma by a micro wave is formed at the inside; and a cavity arranged so as to surround the discharge tube 4 and determining an electric field distribution of the discharge tube 4 and decomposes the organic halogen compound flowing in the discharge tube 4 in the thermal plasma. The apparatus is characterized in that an upstream fixing means for fixing the upstream side of the discharge tube 4 and an insulation guide 26 for fixing the downstream side of the discharge tube are provided.