A control station installed on earth comprising: a reception-quality estimating unit to calculate a reception-quality estimate values and an interference amount estimated value, the reception-quality estimate values being estimated values of received signal quality at plural candidate receiving stations for receiving data transmitted from the transmitting antenna of a transmitting station mounted on a satellite or on an aircraft, the interference amount estimated value being an estimated value of an interference amount received by a receiving station of another radio communication system ; a beam control unit to determine an irradiation direction of the transmitting antenna and, out of the plural candidate receiving stations installed on earth, the at least one receiving station that receives the data transmitted from the transmitting antenna, on the basis of the reception-quality estimate values and the interference amount estimated value; and a transmitting unit to transmit, to the transmitting station, the irradiation direction of the transmitting antenna determined by the beam control unit, wherein the beam control unit is configured to calculate an evaluation value and to determine, on the basis of the evaluation values, the irradiation direction of the transmitting antenna and the receiving station that receives the data, the evaluation value being a sum of a first value and a second value, the first value being obtained by multiplying each of the reception-quality estimate values by a weighting coefficient ( α ), the second value being obtained by multiplying the interference amount estimated value by a weighting coefficient ( β ). a reception-quality estimating unit to calculate a reception-quality estimate values and an interference amount estimated value, the reception-quality estimate values being estimated values of received signal quality at plural candidate receiving stations for receiving data transmitted from the transmitting antenna of a transmitting station mounted on a satellite or on an aircraft, the interference amount estimated value being an estimated value of an interference amount received by a receiving station of another radio communication system ; a beam control unit to determine an irradiation direction of the transmitting antenna and, out of the plural candidate receiving stations installed on earth, the at least one receiving station that receives the data transmitted from the transmitting antenna, on the basis of the reception-quality estimate values and the interference amount estimated value; and a transmitting unit to transmit, to the transmitting station, the irradiation direction of the transmitting antenna determined by the beam control unit, wherein the beam control unit is configured to calculate an evaluation value and to determine, on the basis of the evaluation values, the irradiation direction of the transmitting antenna and the receiving station that receives the data, the evaluation value being a sum of a first value and a second value, the first value being obtained by multiplying each of the reception-quality estimate values by a weighting coefficient ( α ), the second value being obtained by multiplying the interference amount estimated value by a weighting coefficient ( β ). <EOS>