PROBLEM TO BE SOLVED: To provide a method for producing food product by carrying out an electrodialysis treatment using an ion exchange membrane that has a long membrane life and has a high membrane stain resistance, and to provide a food production system comprising an electrodialysis treatment unit.SOLUTION: (1) A method for producing food product in which at least an electrodialysis treatment is carried out for a raw food product material and at least a portion of an electrolyte which is removable by the electrodialysis treatment, is removed, is characterized in that the electrodialysis treatment is carried out by employing a cation exchange membrane that contains a vinyl alcohol copolymer having an anionic polymer segment with anionic group and a vinyl alcohol polymer segment, and that has a micro phase separation structure whose domain size (X) is within a range of 0nm
