To enable the non-pollution treatment of wastes so as to lessen the decomposition hazardous chlorine compounds (dioxins, PCBs, etc.), to ≤0.1 nanogram at a relatively low heating temperature of (150 to 500°C) and to lessen the elution of heavy metals from the wastes.

The decomposition of the hazardous chlorine compounds (dioxins, PCBs, etc.), and the elution of the heavy metals may be lessened by adding chemicals (phosphoric acid compounds, dechlorination treating agents 'alkaline earth metals, alkaline metals, amphoteric oxides, etc.'), to materials to be treated (the ash generated from power plants, burnt ash, flying ash, contaminated soil, sewage in sewer treatment, etc.), contg. hazardous chlorine compds. (dioxins, PCBs., etc.), mixing the mixture and subjected to the mixture to agitating, mixing and heating treatments by using a vibration fluidized bed device.