Image input device and personal authentication device

An image input device is disclosed, including: a lens array in which a plurality of lenses are arrayed; a shielding member configured to prevent a crosstalk on an image surface of light rays passing each of lenses of the lens array; a flat board member configured to regulate a position of a living body in a lens optical axis direction of the lens array when contacting the living body; an image pickup part configured to include an image surface and pick up a compound eye image, which is a set of reduced images of an object inside the living body which position is regulated by the flat board member, the reduced images approximately formed on the image surface by the plurality of lenses of the lens array; and a process part configured to re-compose a single image from the compound eye image picked up by the image pickup part. The image input device inputs the single image re-composed by the process part as an object image.