A high-speed wireless LAN system is disclosed. The system includes a mobile station for transmitting/receiving data encrypted by a predetermined encryption method, communicating the data to associated access points by an ultra wide-band (UWB) communication method, and communicating an encryption key according to the encryption method to said associated access points by an optical or infra-red (IR) communication method; the plurality of access points, installed in a plurality of predetermined service areas, for relaying between the mobile station and a gateway of a remote place by communicating the data and the encryption key with the mobile station located in the corresponding service area by the UWB and the optical or IR communication methods and transmitting/receiving the data and the encryption key to/from the gateway by an optical communication method; and the gateway for providing an optical interface between an internal network and an external network, being provided with a plurality of gateway sub-modules for transmitting/receiving the data and the encryption key by communicating with the plurality of access points by the optical communication method, and transmitting a subscriber service transmitted from the external network to the corresponding access point.