PURPOSE: A germicidal sterilizer composition for a hypochlorous weak acid solution and a method for manufacturing sterilized water using the same are provided to suppress the production of a hydrochloric acid gas or a hydrogen gas in electrolysis and to suppress adhering of a salt to an electrode.CONSTITUTION: A method for manufacturing sterilized water using a germicidal sterilizer composition for a hypochlorous weak acid solution comprises the following steps: a bay salt or a refined salt in a solid phase including sodium chloride and an additive composition for sterilization mixed with an organic acid powder in a solid phase are provided in a powder form or a tablet form(S21) an aqueous solution of a weak acid is obtained by injecting the additive composition for sterilization into water within an electrolytic cell and dissolving the same(S22) an electrode structure comprised of an anode electrode and a cathode electrode sunk in the aqueous solution of the weak acid is electrolyzed in the electrolytic cell by applying a DC voltage(S23) and the DC voltage applied in the electrode structure is blocked when hypochlorous acid sterilizing water which is pH 4.5-6.5 and in which an amount of remaining chlorine is 10-200 ppm is generated by electrolysis of the weakly acidic aqueous solution(S24).COPYRIGHT KIPO 2013[Reference numerals] (AA) Start (BB) End (S21) Obtain a slightly acid aqueous solution by putting and dissolving a sterilizing additive composition, which is prepared in a powder or tablet form by mixing bay salt and organic acid powder so that 80-98wt% of sodium chloride and 2-20wt% of organic acid according to the electric conductivity of water to be made into sterilized water are mixed, in the water in an electrolytic cell (S22) Apply a DC voltage to an electrode structure submerged in the slightly acid sodium chloride aqueous solution in the electrolytic cell, using a titanium electrode coated with iridium oxide as an anode electrode and a titanium electrod
