1. An image judging apparatus, comprising: a candidate region extracting means for extracting candidate regions for predetermined patterns from medical image data; an inner/outer outline image extracting means for extracting inner/outer outline images corresponding to an inner/outer outline region, which are in the vicinity of the outline of the candidate regions extracted by the candidate region extracting means; a pattern judging means for judging the type of pattern within the candidate regions, by employing characteristic amounts of the inner/outer outline image extracted by the inner/outer outline image extracting means; a density pattern extracting means, for extracting density patterns, which are present within unit pixel groups that constitute the inner/outer outline images, extracted by the inner/outer outline image extracting means; a presence frequency calculating means, for judging which of the density patterns the unit pixel groups of the inner/outer outline images are similar to, and calculating presence frequencies by counting the presence of the similar density patterns within the inner/outer outline image; and a classifying means, for classifying the inner/outer outline images according to the type of pattern, based on the presence frequencies of the density patterns; wherein the pattern judging means judges to which classification the candidate region belongs, from among the classifications of the inner/outer outline images, which were classified according to the type of pattern by the classifying means, by employing the presence frequencies of the density patterns therein, derived by the presence frequency calculating means, as characteristic amounts; and the inner/outer outline region includes the entire outline of the candidate regions.