Provided is a water supply unit in a sterilizing and cleaning system using sterile water such as strong-acid electrolyzed water, especially, a water supply unit suitable for sterilizing an appliance or a human body or neutralizing a point being treated. The water supply unit in a sterilizing and cleaning system using sterile water comprises a first storage tank for storing sterile water and a second storage tank for storing aqueous solution of antioxidant, and can supply the sterile water and aqueous solution of antioxidant from takeout water channels which connect the sterile water and aqueous solution of antioxidant, separately, to apparatuses in use through water supply pipes connected with the first and second storage tanks, respectively.
