An optical fingerprint image input device for a mobile apparatus includes: a plate-shaped fingerprint contact member; a distortion correcting member for correcting distortions; light sources disposed at both sides of the fingerprint contact member, other than an inclined surface or a back light source in a liquid crystal display element; focusing means disposed at an inclined surface side of the distortion correcting member; and an image sensor. In other words, the fingerprint contact member and the distortion correcting member having respective set-up inclined angles are disposed to discern sweat, water or oil and to correct a trapezoidal distortion which is a disadvantage that occurs when a thin fingerprint contact medium is used, and to form a lens system comprised of a cylindrical lens and a spherical lens for adjustment of a ratio of transversal to longitudinal widths of an image.