To purify by materializing the effects of prompt, complete disinfection, inactivation, and insecticide on a wide range of microorganisms including bacteria, viruses, amebae, and crustacean larvae and to promptly decompose and peel off coats and stains of resin, oil and fat, etc.

In a purification method in which ozone water is applied to microorganisms such as protozoans and plankton, bacteria, and viruses or things with which they live to annihilate them, or to oil and fat, resin, and other pollutants which adhere to objects to peel off them, the concentration of the ozone water is made to be 20ppm or more to accomplish complete, prompt purification.