PROBLEM TO BE SOLVED: To provide a medical image processor capable of acquiring a blood vessel image which allows a user to more clearly identify a blood vessel into which a contrast medium flows.SOLUTION: The medical image processor has a blood vessel image generation part and a pixel value scale generation part. The blood vessel image generation part acquires a change with time in the concentration of a contrast medium on the basis of at least X-ray contrast image data, and generates blood vessel image data having a pixel value corresponding to a time when the concentration of the contrast medium comes to meet a specific condition in accordance with a gray scale or a color scale. The pixel value scale generation part creates the gray scale or the color scale by assigning the change in the pixel value to a period shorter than the period from the initial time to the end time of the change with time in the concentration of the contrast medium.SELECTED DRAWING: Figure 3
