Interference cancellation repeater is, by removing the first transmission processing unit and the interference signal from the digital input signal for converting the RF input signal input via the link antenna coupled to the base station and communicatively to a digital input signal and outputting an interference cancellation signal interference remover, and converting the interference canceled signal to the RF output signal and to detect a gain variation of the second transmission and reception processing section, and the interference cancellation based on the interference removing signal repeater for amplifying the RF output signal, the gain of the interference cancellation repeater When the change is detected, an RF input signal, the interference cancellation signal and the current gain of the RF output signal of the interference removing at least through one of the intensity control relay device gradually to the target gain (gradually) changes the gain control section for.