A handover method, in a wireless communication system having a mobile station and a plurality of base stations, for performing handover of the mobile station from a connected base station to a neighbor base station, the method having the steps of: deciding that neighbor base station information non-reception handover is establish; searching a connectable neighbor base station; acquiring identification information for the neighbor base station; transmitting a handover request including the acquired identification information; transmitting, in the connected base station received the handover request, to the mobile station, service level information included with in a handover response, and deciding a handover destination based on the service level information.