A feature value calculating section 43a calculates a feature value from a medical image picked up of a living mucous membrane, an extraction section 43b extracts a living mucous membrane microstructure based on a calculated feature value, the feature value calculating section 43a further calculates a feature value from an extracted living mucous membrane microstructure, and a region division section 43c divides the structure into partial regions according to a predetermined condition based on a calculated feature value.
