PURPOSE: To cancel complication for laying a cable and to decrease the number of radio equipments to be installed on the side of a master station concerning the radio LAN system for constructing a radio LAN between a host computer at the master station and respective personal computers at plural slave stations while using the radio waves of a millimeter wave band.

CONSTITUTION: The radio wave outputted from a master station equipment 2 is reflected on a rotary reflection board 10, transmitted to a reflection board 12 of a slave station equipment 5, for example, selected corresponding to the rotating position of the rotary reflection board 10, reflected on this reflection board 12 and arrived at the slave station equipment 5. A slave station transmitting means inside the slave station equipment 5 detects the reception level of the radio wave from the master station equipment 2 and transmits the radio wave to the master station equipment 2 while the detected reception level exceeds a prescribed value. By suitably setting the rotating speed of a rotary driving means 11 and the directivity of respective antennas at the master station equipment 2 and slave station equipments 5 and 8, sufficient communication is enabled while the rotary reflection board 10 faces to the slave station equipments.