1. A fingerprint reading method comprising: a first step of irradiating a detection beam having a first luminescent color onto a fingerprint collation surface against which a finger tip is pressed to thereby acquire a first image corresponding to reflected light from said fingerprint collation surface; a second step of irradiating a detection beam having a second luminescent color different from said first luminescent color onto said fingerprint collation surface against to thereby acquire a second image corresponding to reflected light from said fingerprint collation surface; and a third step of comparing said first image with said second image to determine authenticity of said finger tip pressed against said fingerprint collation surface.