1. A lip categorizing method comprising: categorizing lips using the size and shape of lips as viewed from the front of a face as a first categorization index and using the three-dimensional form of the lips as a second categorization index, in order to enable determination of a form image of the lips, wherein the first categorization index includes as indices at least the lateral width of the lips, the form of the crests and trough of the lips, and the form of the bottom of the lower lip, while the second categorization index includes as indices at least whether the contour shape of the lips is linear or curved, and the three-dimensional form of the lips.