An object classification device (10) includes a keyword determining unit (22), a keyword ordering unit (23) and a classifying unit (24). The keyword determining unit (22) determines keywords for one or plural objects. The keyword ordering unit (23) orders the plural determined keywords based on a conceptual hierarchical structure which is a structure that hierarchically represents concept of words. The classifying unit (24) classifies the objects so as to be associated with the ordered keywords.
