PROBLEM TO BE SOLVED: To provide a medical image processor and a medical image diagnostic apparatus, measuring a plaque adhering shape of a blood vessel in an optional direction and displaying various contraction indexes with a medical image.SOLUTION: A medical image processor and a medical image diagnostic apparatus include: a blood vessel extract part for extracting a blood vessel from medical image data a blood vessel cross section extract part for generating a blood vessel cross section vertical to the blood vessel core line at a predetermined position of the blood vessel, and extracting the inner wall of the blood vessel from the blood vessel cross section a scale setting part for taking a closed curve fitted to the inner wall of the blood vessel and the central point of the closed curve as a scale reference line and a scale central point an observation direction setting part for setting a predetermined observation direction to the scale central point a constriction index measuring part for measuring a constriction index of the blood vessel cross section in the observation direction using the graduations of the scale a color mapping part for coloring corresponding to the measured value of the constriction index and a display control part for displaying one or more colored blood vessel sections on a monitor according to a predetermined display mode.
