A paper sheet authentication apparatus determines the type of the paper sheet by using a characteristic other than a fluorescent light characteristic, sequentially emits excitation lights of different wavelengths on the paper sheet, measures an intensity of light per wavelength within a predetermined range emitted by a fluorescent material applied to the paper sheet, and acquires fluorescent light characteristic data as the result. The paper sheet authentication apparatus performs the authentication of the paper sheet by using fluorescent light characteristic data of a genuine paper sheet previously stored per type of the paper sheet or a threshold calculated therefrom and the acquired fluorescent light characteristic data.