Support information effective in diagnosing chronic obstructive pulmonary disease is provided from a chest volume image. A storage device (112) of a medical image processing apparatus stores the data of a plurality of images in different respiratory phases which represent the morphology of an object chest portion. A vector calculation processing unit (121) calculates the motion amount of a region between the plurality of images for each pixel or area. A level decision unit (123) decides a level concerning the severity of chronic obstructive pulmonary disease for each pixel or area based on a combination of at least two of a motion amount, a feature value obtained from pixel values of image, and the change rate of the size of the area.