To easily acquire high quality latest information from a web site by constructing a data base widely covering web sites carrying only information having a definite or higher evaluation in various fields.

This system is provided with a data base server 14 equipped with a storage means for storing data related with an information source accessible through a network 11 and a site retrieving robot server 16 for extracting the data related with the information source by performing access to the storage means of the data base server 14, and extracting reference information included in the information source by performing access through the network 11 to the information source, and extracting data related with a new information source carrying the reference information by performing access through the network 11 to the new information source, and storing it in the storage means of the data base server 14.