The present invention describes an authentication method applied in a Wireless LAN. In accordance with the present invention, it is not necessary for the user to register on the Internet supply provider (ISP) before using. In other words, when the user is in urgent need of checking network information, the user transmits the identification data and the required connection time to the account server through the safe physical connection line between the user and the account server. At the same time, the server receives the fee according to the connection time.