Transmission power of each base station of a secondary system is determined in such away that a transmission capacity of the secondary system is increased as much as possible while interference with a first radio system (primary system) is suppressed by properly controlling the transmission power of a plurality of second transmission stations. A second transmission station transmission power determination means is provided, which determines the transmission power used in each of the second transmission stations based on a first condition that satisfies an allowable value in relation to a system interference amount as an interference amount given to a first reception station as a predetermined reception station of the first radio system by all of the plurality of second transmission stations as transmission stations of a second radio system using a frequency band allocated to the first radio system or a frequency band allowed to be preferentially used.