PROBLEM TO BE SOLVED: To provide a method for manufacturing water for manufacturing a toiletry product which does not cause changes in quality of a sensitive compound, such as a dye and a perfume, due to a hypochlorite by deactivating the hypochlorite in sterile water obtained through a treatment by the hypochlorite.SOLUTION: The method for manufacturing the water for manufacturing the toiletry product includes adding an isothiazolone compound to the water that contains the hypochlorite, and deactivating the hypochlorite in the water.
