Good transmission performance is obtained even when the difference between the number of transmit antennas and the number of receive antennas is small. A modulation symbol is subjected to spreading and code multiplexing in a receive antenna direction of a terminal device, is subjected to precoding, and is transmitted. A spreading ratio of a spreading code for performing the spreading in the receive antenna direction is equal to the number of receive antennas of the terminal device. Spreading code multiplexing is performed in the receive antenna direction. Thus, it is possible to provide a base station apparatus and a terminal device providing good transmission performance by changing the number of multiplexing operations even when the difference between the number of transmit antennas and the number of receive antennas is small.