1. A high-speed roaming method of a wireless LAN comprising a network, a plurality of access points provided in the network, and a mobile terminal that is radio-connected to one of said plurality of access points via a communication system using a frequency hopping, wherein each of said access points registers previously a predetermined number of access points out of respective neighboring access points as neighboring access points, sends out hopping information of the own access point thereof periodically to the network at mutually different timings, receives the hopping information of the neighboring access points out of respective access points to construct the own access points thereof as a database, and synchronize all access points in a same subnet of the network and sends out radio beacons synchronously from said access points; and said mobile terminal monitors said radio beacons of a connected access point and downloads hopping information of the neighboring access points from said connected access point, monitors radio beacons of said neighboring access points based on the hopping information, construct the monitored hopping information as a database to always compare radio environments, and select and connect the access point having a best radio situation by referring the database of said neighboring access points when a quality of the radio beacon of said connected access point is reduced lower than a predetermined value.