To provide an image processing device and an image processing method capable of controlling contrast of a diagnosed part without greatly changing the characteristic of the entire image, and improving the diagnosis efficiency, an image processing device 100 sets a search pixel range and a search region to search for a representative pixel value as reference upon emphasis on the contrast of a diagnostic image as image data of a diagnosis object, calculates the representative pixel value for emphasis processing based on the set search pixel value range and the search region, and generates an emphasized image where the contrast of the entire diagnostic image is emphasized with the representative pixel value as reference. Further, the image processing device 100 calculates an emphasis region as a region where the contrast is emphasized from differential information between the diagnostic image and the emphasized image, and generates a partially emphasized image as an image where the contrast of the emphasis region is emphasized.