A wireless transmitter and receiver increase a desired/unwanted (D/U) ratio of a correlation output without increasing the number of data in an ultra-wideband direct spread pulse communication system for transmitting and receiving two series of data through different spreading code streams. In the spreading codes used in matched filters of the wireless transmitter, (2*N−2)-th and (2*N)-th values of a cross-correlation signal between first and second spreading codes are greater than 0, (2*N−3)-th and (2*N+1)-th values of an auto-correlation signal of the first spreading code are less than 0, and (2*N−3)-th and (2*N+1)-th values of an auto-correlation signal of the second spreading code are less than 0. The peak value of the cross-correlation signal does not need to be small, and since a value other than the peak value does not become large, the D/U ratio can increase.