Provided is a multi-antenna relay device. The multi-antenna relay device having first to n-th (n is a natural number of 2 or more) channel formed between receiving antennas and transmitting antennas corresponding to each other, comprising: first to n-th channel interference cancellation units, respectively, included in a corresponding channel among the first to n-th channels and canceling first to n-th channel interference signals corresponding to signals radiated through the first to n-th channels from signal input into the corresponding channel in real time.