An authentication apparatus that authenticates individuals with the use of features of a living body includes an input device for placing the living body thereon, an imaging device that images the living body, an image processing unit that processes an image taken by the imaging device, the features of the living body, a plurality of light sources for imaging the living body, and a light guide member. The authentication apparatus also includes first feature data registered in advance, a storage device that stores the first feature data therein, second feature data indicative of the features of the living body imaged by the imaging device, and a checking processing unit that checks the first feature data against the second feature data. The plurality of light sources is arranged on a lower portion of the light guide member, and the plurality of light sources is sequentially turned on.