The present invention provides a discrimination medium A for discriminating the authenticity of an article by providing an optically discriminating mark on the article. A film 20 having a light reflecting layer of a polymer cholesteric liquid crystal having a circular polarization light selectivity for reflecting a specific circular polarization light is fixed to a part of the surface of a support 10. A printed portion is made by printing on the portions other than the film 20 of the support 10 in substantially the same color as that shown when the film 20 is viewed from the front. The discrimination medium A appears to be red at the support 10 and the film 20 when viewed from the front (although the film has a metallic luster), but at a larger viewing angle, the film 20 changes to blue by the blue-shift of the polymer cholesteric liquid crystal so as to exhibit a color different from that of the support 10.