KEYWORD RELATED PLACE NAME EXTRACTION DEVICE, METHOD AND PROGRAM

PROBLEM TO BE SOLVED: To extract a place name related to a keyword by taking into consideration the validity of the place name and the extent of the place name.SOLUTION: Patterns are extracted on the basis of character strings between a keyword and a place name acquired by referring to a document database on the basis of a pair of the keyword and the place name; N higher-order patterns having high reliability appearing with a plurality of pairs of the keyword and the place name are selected from among the patterns; and pairs A of the keyword and the place name corresponding to the selected patterns are acquired. The validity of the place name included in the pairs A is determined, and a place name score is calculated for the place name included in pairs B of the keyword and the place name obtained by eliminating pairs of the keyword and the place name determined not to be valid. Pairs of the keyword and the place name appearing with a plurality of patterns are selected from among the pairs B on the basis of the place name score. The above processing is repeated predetermined times.