A handover method in a wireless local area network (WLAN) environment, a mobile node device that carries out a handover in a WLAN environment, and a beacon signal structure are provided. The handover method involves receiving a beacon signal containing access router identification information; and carrying out a handover based on the access router identification information contained in the beacon signal. The mobile node device includes a beacon signal reception unit for receiving a beacon signal containing access router identified information, a determination unit for comparing access router identification information from the beacon signal with that of a previous access router and a handover performing unit for carrying out a handover based on a result of the determination from the determination unit. The beacon signal structure, which is used for carrying out a handover in a WLAN environment, includes a reserved field into which access router identification information is inserted.