1. An information retrieval apparatus comprising: meta-data specifying means for specifying at least one attribute of information from a plurality of original data described in various forms of description; and pattern learning means for creating at least one rule for extracting information including the specified attribute based on said specified attribute, wherein said pattern learning means creates said at least one rule by abstracting information including said specified attribute according to said plurality of original data, wherein one of said at least one rule may be created to recognize a plurality of different instances of information including said specified attribute.