It is possible to prevent lowering of a throughput of a radio communication system even when propagation path environments of an uplink line and downlink line are asymmetric. A maximum proper value calculation unit (115) calculates a maximum proper value from a channel matrix. A maximum proper value comparison unit (116) compares the maximum proper value with a maximum proper value of the downlink line reported separately from a base station. According to the comparison result obtained by the maximum proper value comparison unit (116), a proper mode initiative instruction unit (117) decides to pass the proper mode initiative to a communication partner or to the local device. When the initiative is to be passed to the local device, this fact is reported to a proper bam correction unit (118). When the proper beam correction unit (118) gets the proper mode initiative, the proper beam correction unit (118) corrects the correlation matrix by using the proper values of both of the downlink line and the uplink line and instructs a directivity forming unit (103) to form a proper beam according to the correlation matrix after the correction.