A command processing method for a radio LAN system composed of a plurality of terminals and at least one base apparatus is disclosed which prevents users of the terminals from suffering from confusion or conflict between them with regard to handling of a command issued from any of the terminals and from misunderstanding that the system has failed. When a channel changing command or a like command is issued from a terminal, the base apparatus determines whether or not the received command is a competitive command whose acceptance may result in the disturbance of reception of data of any other terminal. If the received command is a competitive command, then the base apparatus rejects the command and issues a notification of the rejection to the terminal which has issued the command. When a particular condition is satisfied such as when the priority of the terminal which has issued the command is higher than that of any other terminal receiving data, then the base apparatus may accept the command.