A relay station to which network sharing is applied, wherein it is possible to appropriately allocate between multiple operators a shared band frequency shared by the multiple operators, and to improve the frequency use efficiency. In a relay station (100), a band frequency allocation determination unit (107) determines the bandwidth for each operator within a shared band frequency, which is shared by multiple operators and used between the relay station (100) and a mobile station, on the basis of the quality of a first line between the relay station (100) and the base stations of the operators and on the basis of the status of a second line between the relay station (100) and the mobile stations of the operators. A signal generation unit (108) allocates the signal of the operators to a resource on the basis of the bandwidth for each operator in the shared band frequency.