An authentication apparatus includes a prism, an imaging unit, a visible light source and an infrared light source. The prism comprises: a contact surface contacted with the living body a reflection surface contacted with the contact surface, and totally reflect light by the visible light source from a concave portion of the living body and a convex portion of the living body, and light by the infrared light source from an inside of the living body and an imaging surface configured to be opposed to the contact surface, in contact with the reflection surface, and provided at an angle such that the light from the concave portion of the living body cannot be reached, and the light totally reflected by the reflection surface and the light from the convex portion of the living body can be transmitted. The imaging unit images the light which is transmitted through the imaging surface.
