Abstract: A waste substance such as toxic compounds used in chemical weapons and industrial wastes including incineration ash is treated by a thermit reaction agent by way of supplying the waste substance to a combustion region of the thermit reaction agent or by adding way of heating the blended material comprising the waste substance and thermit reaction agent. The waste substance is fed into the combustion region of a thermit-type hypergolic fuel containing as its principal component a thermit reaction agent composed of an aluminum powder and a metal oxide powder, thus breaking down such a waste substance using the combustion heat of the thermit-type hypergolic fuel. The waste substance can be blended with a thermit reaction agent and fed into a combustion chamber so that the blended material is heated by way of a burner, so that the blended material is directly heated by a burner during the continuation of thermit reaction following the start of the thermit reaction of the thermit reaction agent.