An image processing apparatus includes a central-portion extracting unit, a classifying unit and a determining unit. The central-portion extracting unit extracts edges from an image area and extracts a plurality of central portions of areas each of which is sandwiched between the edges. The classifying unit groups the central portions by classifying adjacent central portions that have no edge therebetween into a single group. The determining unit determines an area of finger, the area of finger being surrounded by the central portions classified into a group by the classifying unit and peripheral edges of the central portion, the area of finger being an area where a ratio of a luminance gradient in a short side direction to a luminance gradient in a long side direction is within a predetermined threshold.