19. An information retrieval method of retrieving a name including characters input in a computer from a database, the method comprising: retrieving, by the computer, the name including the input characters from a database for storing the name, an attribute word associated with the name, and a degree of relevance indicating a degree of relevance between the name and the attribute word; outputting the retrieved name as a candidate name; extracting an attribute word associated with the candidate name from the database; and outputting the extracted attribute word and the candidate name to an output unit of the computer, wherein the extracting an attribute word associated with the candidate name from the database comprises: obtaining a degree of relevance of the candidate name associated with the attribute word from the database with respect to a combination of the extracted attribute words; calculating a degree of independency indicating a degree of difference between the extracted attribute words; calculating a degree of coverage indicating an extent to which the combination of the extracted attribute words covers the candidate names; calculating a degree of equality indicating uniformity of a number of corresponding candidate names for each attribute word; calculating a score of the combination of the attribute words based on at least one of the calculated degree of independency, the calculated degree of coverage and the calculated degree of equality; and outputting the combinations of the attribute words to the output unit in a descending order of the score.
20. The information retrieval method according to claim 19 , wherein the attribute word stored in the database comprises a morpheme constituting a part of the candidate name.