An image processing device including: an image acceptance unit accepting a first image and a second image; a perimeter measurement unit measuring a perimeter of an object image within the first image or an object image within the second image; an area measurement unit measuring an area of the object image within the first image or the object image within the second image; a first reference area generation unit generating a first reference area based on the perimeter and area measured; a datum point extraction unit extracting datum points from the first image and the second image; and a first match judgment unit making the datum points coincide with each other, and judging whether or not the object image within the first image and the object image within the second image are matched, based on densities of the first and second image within the first reference area.