A charged water particle is disclosed which contains radicals such as hydroxyl radicals or superoxides and has a particle diameter of nanometer size, for example, a particle diameter of 3-100 nm. Such a charged water particle is produced by applying an electric field with an intensity of 700-1,200 V/mm between a pair of electrodes while supplying water between the electrodes. By spreading the thus-obtained charged water particles in an indoor space, bad odor components/bacteria in the indoor space can be efficiently eliminated.