INFORMATION STORAGE DEVICE, PROGRAM THEREFOR AND MEDIUM RECORDED WITH THE PROGRAM, INFORMATION RETRIEVAL DEVICE, PROGRAM THEREFOR AND MEDIUM RECORDED WITH THE PROGRAM

摘要

PROBLEM TO BE SOLVED: To certainly retrieve desired information from a plurality of pieces of information stored and expressed by a natural language with suppressing output of unnecessary information. SOLUTION: Index information comprising at least two pieces of word information having predetermined relation and relational information showing the relation between the word information is extracted from natural language information expressed by the natural language including the plurality of pieces of word information by an index information extraction part 2 and is stored in an information storage part 1 together with the natural language information. When retrieving the information, the index information is inputted to an information retrieval part 4 by an index information input part 3 on the basis of user's operation and is collated with the index information stored in the information storage part 1.