A label (1) of this invention includes an optical function layer (13) configured to pass light of a certain wavelength, a light absorption layer (15) facing the optical function layer (13) and configured to absorb the light of the wavelength, and a light scattering layer (12) intervening between the optical function layer (13) and the light absorption layer (15) and including hollow bodies configured to scatter the light of the wavelength. The light scattering layer (12) is configured to raise a transmittance at the wavelength upon receiving external heat.