A carrier leakage correction method for a quadrature modulator according to an embodiment includes inputting a test signal with a frequency fBB to a transmitter and up-converting the test signal with a frequency fL0 and down-converting with the frequency fL0. A frequency 2fBB component is detected in the down-converted test signal. One or a plurality of parameters of the transmitter is/are adjusted so as to reduce a magnitude of the detected frequency 2fBB component in the test signal.