To enable use of basic authentication for a Web page (dynamic Web page) identified by a dynamic URL.

When authenticating by confirming whether or not basic authentication information transmitted from a browser 101 is previously stored in a database 300 in a storage device, a server apparatus 200 obtains information of a domain part and subsequent ones in the URL transmitted from the browser by a URL determination section 201, determines whether (Yes) or not (No) the obtained information is associated as an object of basic authentication and stored in the database 300 in advance, and if the determination result indicates Yes, by an ID/PASS determination section 202, returns a basic authentication screen to the browser 101 to perform basic authentication using the basic authentication screen.