The present invention relates to a technique implementing a density adjustment fitted to an image, concretely, an image processing apparatus for (1) judging the kind of a read image with a high accuracy, and (2) producing an arbitrary .gamma. curve. The apparatus includes: a histogram calculation section for calculating a histogram of an image; a highlight part detection section for detecting a highlight part from the histogram; a shadow part detection section for detecting a shadow part from the histogram; a .gamma. curve production section for producing a .gamma. curve by using .gamma. values corresponding to each of the highlight part and the shadow part, both obtained on detection results of the highlight part detection section and the shadow part detection section, respectively; and a density adjustment section for performing a density adjustment of an image on the .gamma. curve produced by the .gamma. curve production section.