PROBLEM TO BE SOLVED: To make the determination of positions of plaques easy and to make the determination of the quantity and characteristics of the plaques in a projecting direction easy when converting 3D data to a 2D projecting image.SOLUTION: A medical image processor has a projecting image generating section 15 generating projecting images from 3D CT data relating to a subject, extracting a plurality of plaque areas with different rigidities based on a plurality of CT value ranges from the 3D CT data, and generating plaque projecting images aiming plaque areas, and a display sections 16, 17 which superposing the plaque projecting images on the projecting images and displaying the same and in which each pixel constituting the plaque projecting images has a concentration value corresponding to the CT value range of each plaque range and has a color value corresponding to the area ratio of the crosssectional area of the plaque area to the total of the crosssectional area of the plaque area and a blood vessel crosssectional area.
