The present invention relates to a method for measuring metal ion permeability of a polymer film, comprising the steps of applying a voltage to the polymer film, while at least one side of the polymer film is brought into contact with an electrolyte comprising metal ions, an organic solvent and an aqueous solvent; and measuring the change rate of resistance or change rate of current of the polymer film according to time, after the voltage is applied, and a device for measuring metal ion permeability of a polymer film used therefor.