A radio transmitter having a plurality of transmitting antennas (18a, 18b) for transmitting a transmission signal in units of sub-carriers by allocating said transmission signal to said transmitting antennas (18a, 18b), comprising: a sub-carrier modulation part adapted to modulate an input transmission signal for each sub-carrier; a transmission signal allocation part adapted to allocate said transmission signal modulated for each of the sub-carriers to each of said transmitting antennas; and a transmission control part adapted to determine respective multiplexing numbers for performing spatial multiplexing for each of the sub-carriers based on information received from another radio communication device as an opposite party, and to perform control to allocate said transmission signal to said plurality of transmission antennas (18a, 18b), wherein: said transmission signal is composed of a plurality of ordered data symbols; said transmission control part is adapted to determine a percentage of the number of data symbols for each value of said multiplexing numbers in accordance with which the data symbols are to be allocated to said plurality of transmission antennas (18a, 18b) sequentially; and said transmission control part is adapted to allocate said transmission signal to said plurality of transmission antennas in descending or ascending order of subcarriers and in ascending order of said multiplexing numbers in accordance with the percentage of the number of data symbols for each value of said multiplexing numbers. a sub-carrier modulation part adapted to modulate an input transmission signal for each sub-carrier; a transmission signal allocation part adapted to allocate said transmission signal modulated for each of the sub-carriers to each of said transmitting antennas; and a transmission control part adapted to determine respective multiplexing numbers for performing spatial multiplexing for each of the sub-carriers based on information received from another radio communication device as an opposite party, and to perform control to allocate said transmission signal to said plurality of transmission antennas (18a, 18b), wherein: said transmission signal is composed of a plurality of ordered data symbols; said transmission control part is adapted to determine a percentage of the number of data symbols for each value of said multiplexing numbers in accordance with which the data symbols are to be allocated to said plurality of transmission antennas (18a, 18b) sequentially; and said transmission control part is adapted to allocate said transmission signal to said plurality of transmission antennas in descending or ascending order of subcarriers and in ascending order of said multiplexing numbers in accordance with the percentage of the number of data symbols for each value of said multiplexing numbers. said transmission signal is composed of a plurality of ordered data symbols; said transmission control part is adapted to determine a percentage of the number of data symbols for each value of said multiplexing numbers in accordance with which the data symbols are to be allocated to said plurality of transmission antennas (18a, 18b) sequentially; and said transmission control part is adapted to allocate said transmission signal to said plurality of transmission antennas in descending or ascending order of subcarriers and in ascending order of said multiplexing numbers in accordance with the percentage of the number of data symbols for each value of said multiplexing numbers.