PROBLEM TO BE SOLVED: To provide a medical image processor capable of associating image groups generated by mutually different reconstruction processing, and a medical image diagnostic device.SOLUTION: A medical image processor of an embodiment includes first reconstruction processing means, first image generation means, second reconstruction processing means, and second image generation means. The first reconstruction processing means performs first reconstruction processing by using photographic data obtained by photographing a subject by medial image photographing means, and creates first volume data. The first image generation means generates a first image group on the basis of the first volume data. The second reconstruction processing means performs second reconstruction processing different from the first reconstruction processing by using photographic data corresponding to a designation image designated from the first image group, and creates second volume data more precise than the first volume. The second image generation means generates a second image corresponding to the designation means on the basis of the second volume data.
