To suppress deterioration of retransmission efficiency and retransmit a transmission signal efficiently, provided are a base station apparatus which divides, in a retransmission block dividing section, a transmission signal into retransmission blocks according to a retransmission block table with which are registered the numbers of the retransmission blocks, each of the transmission blocks is a retransmission unit of a transmission signal, the numbers of the retransmission blocks are required numbers corresponding to the number of transmission antennas and the system bandwidth in case that the maximum value of the size of the retransmission block is fixed to a certain value, and retransmits in downlink transmission signals associated with the divided retransmission blocks, and a mobile terminal apparatus which receives the transmission signals associated with the retransmission blocks from the base station apparatus, and combines the retransmission blocks to restore the transmission signal prior to division.