An image processing method includes identifying a body region in a tomographic image based on pixel values within the tomographic image, extracting a bone muscle region corresponding to essential parts of bones and muscles based on bone muscle pixels having pixel values corresponding to the bones or muscles in the body region, searching boundary points of the bone muscle region from outside a region surrounding the extracted bone muscle region to inside the region, creating a bone-muscle region outer peripheral profile line by joining only boundary points at which each index related to at least one of a length and a slope of a line segment connecting between the adjoining boundary points of the searched boundary points satisfies a predetermined condition, and extracting a visceral fat region comprised of fat pixels having pixel values corresponding to fat in a region lying inside the bone-muscle region outer peripheral profile line.
