A position obtainment means obtains the positions of points in the heart of a subject that are present in at least two three-dimensional volume datasets in a group of three-dimensional volume datasets that have been obtained by imaging the heart of the subject at predetermined time intervals, the points anatomically corresponding to each other, and the at least two three-dimensional volume datasets having been obtained by imaging at different time from each other. A function information obtainment means obtains, based on each of the positions of the points in the heart, which have been obtained by the position obtainment means, function information representing the function of the heart at each point within a three-dimensional space. A display means displays, based on the function information, the motion function of the heart at each of the points in an image that has the shape of the heart of the subject.