To provide a radio LAN communication system in which both a slave unit having a favorable radio wave state and a slave unit having an unfavorable radio wave state can perform data communication with a master unit through a radio LAN at the same degree.

The slave unit 8 includes a data communication storage means 10, a slave unit priority storage means 11 and a slave unit communication control means 12 which transmits communication data when sending a communication request signal to the master unit 7 and receiving a communication permission signal from the master unit 7. The master unit 7 includes: a master unit priority storage means 13; a priority determination means 14 for comparing the priority of the plurality of slave units 8a, b to determine the priority of the slave units; and a master unit communication control means 15 which sends a communication permission signal to the slave unit communication control means 12 of the slave unit 8a having high priority when receiving a communication request signal from the other slave unit 8a during data communication of one slave unit 8b, and transmits a communication no-permission signal or a communication interruption signal to the slave unit communication control means of the slave unit 8b low in priority.

COPYRIGHT: (C)2011,JPO&INPIT