To sterilize pathogenic fungi or pathogenic virus by radiating ultraviolet rays of different wavelengths having no side effects gradually to apply pressure without chemicals.

An ultraviolet ray of 184 nm wavelength is radiated to an oxygen molecule O2 to generate O3, a gas containing the ozone O3 is mixed with water in which pathogenic fungi live and pressurized, then an ultraviolet ray of 254 nm wavelength is radiated to the ozone O3 to generate a singlet state free oxygen 1O2 and the singlet state free oxygen 1O2 is reacted with water to generate the oxidization of hydroxy radical OH to sterilize pathogenic fungi, etc.