A thin-film inspection apparatus calculates a film thickness of a first transparent thin film and a second transparent thin film of an inspection-target substrate including the first and second transparent thin films and a transparent conductive film on a transparent glass substrate. The apparatus has a storage section storing at least two feature-value characteristics in which at least two feature values selected from feature values in a spectral reflectance spectrum; a light irradiation section irradiating the inspection-target substrate with white light through the transparent glass substrate; a light receiving section receiving light reflected from the inspection-target substrate; and an arithmetic section obtaining measurement values of the feature values stored in the storage section from the spectral reflectance spectrum based on the reflected light received by the light receiving section, and calculating the film thickness of each of the first transparent thin film and the second transparent thin film.