Abstract: The accuracy of retrieving or clipping documents is improved. A document to be processed is input via a document input section. Event specifying means looks up knowledge information stored in knowledge information storing means to specify the type of an event described in the input document. Attribute value extracting means extracts, from the document, attribute values of attributes relating to the specified event. Correlating means performs a process of correlating the attribute values extracted by the attribute value extracting means with entities in the real world. Document storing means stores information (normalized information) generated by the correlating means and the document or information specifying a storage location thereof in a manner associated with each other. Document extracting means compares a query input from a user interface section with the normalized information and extracts, from the document storing means, matching documents or information specifying their storage locations.