In order to provide an image processing device which can select and apply an optimal processing algorithm among a plurality of processing algorithms depending on a part of a processing target image and a processing purpose, reference characteristic curve data is calculated in which pixel values are integrated centered on a centroid of a region of interest for a reference image, and the reference characteristic curve data and a processing algorithm according to a processing purpose are stored in advance in an algorithm table 2 in correlation with each other at least for each part.