In order to provide pages relating to a prescribed page to a user in a precise manner over the internet, a site page processor collects pages included at various sites, determines parent-child relationships between the pages, and stores the results of such determinations in a site page data storage section. A related page data processor calculates the relevance between pages using page feature extraction values given weightings taking into consideration at least one of a sibling relationship and a co-parent relationship between pages using data stored in the site page data storage section. Through this page feature extraction, words used in common on pages in link relationships are processed so as not to have a substantial influence on the calculation of relevance. The system can be applied to a server on the Internet for searching for pages relating to a prescribed page.