A spatial multiplex number controlling method and others wherein streams can be separated for each of receivers and the transmission efficiency can be improved. In a receiving apparatus, a PER is calculated from a history of CRC test results per stream multiplex number. A reception quality and an offset corresponding to the calculated PER are fed back to a transmitting apparatus. The transmitting apparatus assigns, based on the fed-back reception quality and offset, the streams, thereby controlling the stream multiplex number.