To continuously perform procedures to remove dioxins from a dioxin- containing gas by employing a fluidized bed decomposition treatment method using a fluid medium having a dioxin decomposition catalytic power.

The decomposition treatment of dioxins is performed by a fluidized bed system using a fluid medium having a dioxin decomposition catalytic power when treating a gas containing dioxins generated in a refuse/ industrial waste incineration furnace or the like. When performing the treatment, the dioxin-containing gas is introduced into a fluidized adsorption column 1, and a combination of an adsorbent and a catalyst is fluidized and, at the same time, moved to guide out the gas as a dioxin-free gas from the top of the adsorption column 1. In this case, the combination of adsorbent and catalyst adsorbs or causes the adhesion of the dioxins or their capturing to produce the dioxin- free gas. The combination of adsorbent and catalyst itself becomes a combination of adsorbent and catalyst adsorbing the dioxins. The combination of adsorbent and catalyst is partially guided out continuously by a removing means 11 provided on the adsorption column 1 to be recycled and circulated through a dioxine decomposition column 2.