A communication device 1 (transceivers 400) transmits a training signal from its own transmitting antenna while performing beam scanning, and a communication device 2 (transceivers 500) receives this training signal in a state where a quasi-omni pattern is generated in its own receiving antenna. Further, the device 1 transmits a training signal in a state where a quasi-omni pattern is generated in the transmitting antenna, and the device 2 receives this training signal by the receiving antenna while performing beam scanning. The device 1 and 2 detects, from respective reception results, transmitting-antenna-setting candidates of the device 1 and receiving-antenna-setting candidates of the device 2, and determines antenna-setting pairs (combinations of antenna-setting candidates). The above-described processes are also performed for a receiving antenna of the device 1 and a transmitting antenna of the device 2. The device 1 and 2 communicates by using the obtained antenna-setting pairs. In this way, when radio communication is performed by using beam forming, the time necessary for finding and setting a beam direction is reduced, thereby reducing the transmission-disconnected time.