The present invention relates to a multiple antenna transmitting/receiving apparatus that performs a hybrid automatic repeat request, and a retransmission method thereof. An initial transmission signal is encoded into the form of an initial transmission matrix and transmitted to the receiving apparatus, the initial transmission matrix corresponding to a linear dispersion code, with a result of error checking performed on the initial transmission signal by the receiving apparatus. When an error is detected in the initial transmission signal, a first retransmission signal is generated by encoding the initial transmission signal in the form of a retransmission matrix and transmitted to the receiving apparatus. The retransmission matrix is formed of constituent elements of the initial transmission matrix but different from the initial transmission matrix, and corresponds to a linear dispersion code having the same capacity and diversity gain as those of the initial transmission matrix.