To allow for obtaining information related to other radio communication information appropriately and at a low load in a plurality of radio communication devices between which the communication distance dynamically varies.

A radio communication system 10 comprises: a master unit 21 which performs device scan by means of a first communication unit 110, obtains information identifying and related to the detected slave unit, compares information identifying the detected slave unit 22 with information identifying slave units 22 stored in a storage unit 104, and if the information identifying the slave units 22 is not obtained from all slave units 22, and obtains information identifying and related to a slave unit 22 from the slave unit 22, whose information could not be obtained, by means of a second communication unit 120; and a slave unit 22 which transmits information identifying its own unit and related information by means of its first communication unit 110 if the master unit 21 performed device scan to it, and transmits information identifying its own unit and related information by means of its second communication unit 120 if the slave unit 22 receives a communication request from the second communication unit 120.