A radio relay station provided with: a donor-side transceiver unit which transmits and receives a donor-side signal, at which a first frequency band is used, to and from a radio base station; a service-side transceiver unit which transmits and receives a service-side signal, at which a second frequency band adjacent to the first frequency band is used, to and from a radio terminal; and a control unit and a control unit which control the donor-side transceiver unit and service-side transceiver unit respectively. The donor-side transceiver unit, when the service-side signal has been received, measures the signal level of the service-side signal at the first frequency band. The control unit and the control unit adjust the shift amount for the second frequency band at the frequency shifter so as to lower the signal level.