1. An information identification device comprising: a light source for irradiating, with exciting light, a light-emitting member containing a rare-earth complex; a measurement section for receiving light emitted from the light-emitting member, and for measuring spectral intensities of the light; a computation section for computing a ratio of spectral intensities at a plurality of different wavelengths among the spectral intensities thus measured; and an identification section for identifying identification information corresponding to the ratio thus computed.