An interference cancellation repeater according to the inventive concept includes: a first transmission/reception processing unit configured to adjust a gain of a radio frequency (RF) input signal input via a link antenna communicatively coupled to a base station; an interference canceller configured to cancel and output an interference signal from an output signal of the first transmission/reception processing unit; and a gain controller configured to extract a signal with constant magnitude regardless of a change in user traffic from the output signal of the interference canceller, and to adjust the gain of the RF input signal to a predetermined level by controlling the first transmission/reception processing unit based on the extracted signal.