Waste materials including chlorine compounds are charged into a fluidized-bed gasification furnace (12) having a first fluidized bed (10) of which fluidizing medium comprises CaO. HCl produced from the waste materials is reacted with CaO which is the fluidizing medium and changed into CaCl2 and changed into a salt, and then discharged from a discharge pipe (32) together with unburned materials. Gas generated as a result of the above-described reaction flows together with CaCO3, which is supplied into a second fluidized bed (16) of a fluidized-bed combustion furnace (14) located above, and are burned within the second fluidized bed (16). CaO is supplied from the second fluidized bed (16) into the first fluidized bed (10) via a supply pipe (18). In this manner, HCl produced from the waste materials is effectively removed. <IMAGE>
