1. A character noise eliminating apparatus for eliminating a character noise which is an atypical shaped background noise from a fingerprint or a palm print image, the apparatus comprising: a character noise area detecting device for detecting a character noise area, which is an area corresponding to the character noise, from the image; a density conversion area layer determining device for setting a plurality of density conversion area layers inside and outside the character noise area; and a density converting device for, as a reference area of a target pixel, setting a neighboring pixel group within the same density conversion area layer as the density conversion area layer to which the target pixel belongs, and generating a density converted image by applying local image enhancement.