PROBLEM TO BE SOLVED: To perform the production of mineral water from seawater by electrodialysis using an ion exchange membrane while preventing the contamination of the ion exchange membrane.SOLUTION: There is provided a method for producing a mineral composition characterized in that, in a method where, utilizing seawater, treatment is performed with an electrodialyzer composed in such a manner that an anion-exchange membrane and a cation-exchange membrane are alternately arranged between an electrode to produce a mineral component-containing composition. The cation-exchange membrane: containing a vinyl alcohol-based copolymer having an anionic polymer segment, which has an anionic group, and a vinyl alcohol polymer segment and having a micro phase separation structure in which domain size (X) lies in the range of 0 nm
