A perfluorovinyloxy polyether carboxylic acid alkali metal salt represented by the general formula is provided: CF2═CF[OCF2CF(CF3)]bO(CF2)aO[CF(CF3)CF2O]cCF(CF3)COOM  [I], wherein M is alkali metal, preferably sodium or potassium, a is an integer of 1 to 6, preferably 2, and b+c is an integer of 0 to 6, preferably 0 or 1. This perfluorovinyloxy polyether carboxylic acid alkali metal salt is produced by subjecting a perfluorovinyloxy polyether carboxylic acid alkyl ester represented by the general formula: CF2═CF[OCF2CF(CF3)]bO(CF2)aO[CF(CF3)CF2O]cCF(CF3)COOR  [II], wherein R is an alkyl group having 1 to 12 carbon atoms, a is an integer of 1 to 6, and b+c is an integer of 0 to 6; to hydrolysis or solvolysis in the presence of an alkali metal hydroxide.