To resolve problems in an increasing tendency of PFC amount flowing into a PFC decomposition apparatus following the market growth in the semiconductor or liquid crystal manufacturing fields, wherein, when decomposing a large flow amount of PFC by a catalyst, the performance of the catalyst becomes low and the durability is deteriorated, unless the active points of the catalyst are effectively used.

Increase of a linear speed of gas passing through a catalyst layer diffuses gas into fine pores of the catalyst to effectively use the active points of the catalyst, thus decreasing reaction load of each active point, enhancing the PFC decomposition performance and durability of the catalyst.