To provide a method that readily evaluates the permeability of chemicals for polymer film.

The characteristics of the evaluating method on the permeability of chemicals for polymer film is as follows; after bring chemicals into contact with one side surface of a polymer film, the total-reflection absorption spectra containing inherent absorbing wavenumber of the chemicals concerned is measured by means of a Fourier-transform infrared spectrophotometer on the opposite side surface to that with which the chemicals concerned is brought into contact to evaluate the permeability of the chemicals concerned on the polymer film concerned.