1. An image input apparatus that inputs an image of an object residing within a living body, the apparatus comprising: a light source that irradiates near infrared light on the living body; a lens array that is arranged at a position facing the living body and includes a plurality of lenses, each of the lenses having a face with zero or negative power arranged at a side facing the living body and a face with positive power arranged at a side facing an image surface; an imaging unit that is arranged at the image surface side of the lens array and is configured to form a compound-eye image corresponding to a collection of ommatidium images formed by the lenses of the lens array; and a reconstruction unit that is configured to reconstruct a single image from the compound-eye image formed by the imaging unit using a parallax between the ommatidium images, said reconstructed single image being input as the image of the object.