<;P>;PROBLEM TO BE SOLVED: To provide a desalting method capable of desalting a used seasoning liquid containing a storage duration improver by efficient electrodialysis. <;P>;SOLUTION: This desalting method from the used seasoning liquid containing a storage duration improver comprises performing desalting by subjecting the used seasoning liquid to electrodialysis treatment, by using a composite anion exchange membrane which has an anionic polymer layer existing on the surface of the exchange membrane. <;P>;COPYRIGHT: (C)2009,JPO&INPIT