Abstract: An apparatus for oxidatively destructing a trace injurious substance includes a structure with anodes, each integrally provided with an electrically conductive oxide on their surface and made of a metal. A partition made of a porous ceramic or resin is provided between the anodes and surrounded by cathodes made of a metal plate having inner walls on both sides to which a noble metal is fused, such that at least two chambers with spaces are formed in a plane symmetrical arrangement to provide an apparatus for oxidatively destructing a trace injurious substance contained in polluted water. The apparatus has a rectangular wave discharging device for applying an electric field to the spaces, such that polluted water flows through the inner space of one of the chambers and is subjected to the irradiation of an electric field, and the supernatant thereafter flows through the inner space of the other chamber and is subjected to the irradiation of an electric field.