To decompose dioxins easily and inexpensively by putting a substance containing the dioxins in a water tank, applying high voltage to it, and decomposing the dioxins by generated high temperature plasma.

When dioxins are decomposed and detoxified, a substance containing the dioxins is put in a water tank of titanium, and a high voltage of about 5-100 kV is applied between the water tank of a negative electrode and a carbon rod of a positive electrode. In this way, high temperature plasma of about 10,000°C is generated in a discharge path, and impact waves of several thousand atm are generated. The dioxins are decomposed by the energy of the impact waves into harmless carbon dioxide, inorganic salts, and water.