1. A medical image segmentation apparatus for generating image data respectively representing plural series of images including at least first and second series of images based on image data representing one series of images including plural axial images, said apparatus comprising: image segmenting means for segmenting one series of images into a first series of images and a second series of images to thereby generate first image data representing the first series of images and second image data representing the second series of images; and segmentation information adding means for adding adjacent image information, which includes information for identification of the second series of images and information representing a positional relationship of the second series of images with the first series of images, to the first image data, and adding adjacent image information, which includes information for identification of the first series of images and information representing a positional relationship of the first series of images with the second series of images, to the second image data.