To solve such a problem that treatment at a high temperature of ≥850°C is necessary and indispensable to discharge of flue gas containing toxic substances (particularly dioxins, or the like) generated when waste is burned, and since it is difficult to separate dust and air from the flue gas treated at the high temperature, the dust-containing flue gas is discharged as it is in the conventional flue gas treatment system using cyclone, or the like, after waste is burned.

This flue gas treatment system is constituted so that toxic substances are burned completely at ≥850°C in a tertiary combustion chamber, dust is removed by applying negative voltage and the toxic substance-burnt dust-removed flue gas is cooled to ≤200°C by an air circulating system. Therefore, this flue gas treatment system exerts no adverse influence on the environment and is safe.