A communication area reservation method capable of operating a plurality of radio systems using communication area reservation signals (NAV) according to the IEEE802.11. According to this method, a communication terminal accommodation apparatus carries out a radio communication with communication terminal apparatuses through an antenna 101, radio section 102, control section 106, logical link control section 104 and medium access control section 103a. Further, a communication area reservation section 107 generates a communication area reservation signal when necessary (e.g., when a communication starts) and this communication area reservation signal is sent to the communication terminal apparatuses through the radio section 102 and antenna 101.