The invention relates to an acid bathing water preparing device.The acid bathing water preparing device comprises a closed container, negative electrodes, positive electrodes and an electrolytic power source, wherein the negative electrodes and the positive electrodes are arranged in the closed container in pairs, and the electrolytic power source is used for supplying power to the negative electrodes and the positive electrodes.The closed container is provided with a water inlet connected with a city supplying tap water pipe and a water outlet.A water permeating diaphragm made of nonconductive materials is arranged between the negative electrodes and the positive electrodes, divides the closed container into a negative electrode chamber and a positive electrode chamber and is provided with micropores with uniform water permeating hole diameters.An activated carbon filter element completely wrapping the negative electrodes is arranged outside the negative electrodes and is closely attached to the water permeating diaphragm.The water inlet is formed in the activated carbon filter element, and the water outlet is formed in a shell of the closed container and communicated with the positive electrode chamber.The acid bathing water preparing device can remove residual chlorine, radon and other pollutants in water and can also produce healthy acid bathing water.