To provide a technique, capable of deciding whether a certain home page is one, to which unauthorized actions are frequently performed by malicious users.

Concerning the home page truth maintaining method for maintaining the truth of a home page, this method has a step for detecting the illegal action to the relevant home page by comparing authentication information for authenticating contents when registering or updating the home page with the present contents of the relevant home page, a step for counting the number of times of unauthorized action detection, showing how many times the unauthorized action, is detected concerning the relevant home page, and a step for controlling the execution of authentication processing of the relevant home page, corresponding to the number of times of illegal action detection of that home page.