1. A cardiac function analysis apparatus comprising: a volume data storage means for storing a group of three-dimensional volume datasets that have been obtained by imaging the heart of a subject at predetermined time intervals; a position obtainment means for obtaining the positions of points in the heart that are present in at least two three-dimensional volume datasets in the group of three-dimensional volume datasets, 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 for obtaining, based on each of the positions of the corresponding 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; and a display means for displaying, based on the function information, which has been obtained by the function information obtainment means, the motion function of the heart at each of the points in an image that has the shape of the heart of the subject.