In order to allow each of communication stations to execute impartial control of accesses to communication media by setting executable-communication ranges of their own independently of each other in a communication environment based on a CSMA method, the present invention provides a radio communication system in which each communication station is capable of checking the occupation state of communication media and setting such an executable-communication range of its own in accordance with the occupation state of the communication media that the number of communication stations coexisting in the executable-communication range is brought to a value within a predetermined range. For example, a specific communication station sets an executable-communication range of its own in order to limit the number of other communication stations capable of communicating with the specific communication station. In addition, a communication station sets an executable-transmission range suitable for an executable-reception range set by itself in order to reduce the degree of non-uniformity of the access control and to minimize the impact of interferences on other communication stations.