A time-domain IQ mismatch detection apparatus for detecting mismatch between an I-channel signal and a Q-channel signal in unit of a sample included in a symbol of an OFDM signal comprises: a first delayer which delays an input I-channel signal by one sample interval; a second delayer which delays an input Q-channel signal by one sample interval; a first phase mismatch detector which multiplies a currently-input I-channel signal with a currently-input Q-channel signal and output a result thereof; a second phase mismatch detector which multiplies the currently-input I-channel signal and the delayed Q-channel signal and output a result thereof; a third phase mismatch detector which multiplies the delayed I-channel signal with the currently-input Q-channel signal and output a result thereof; and a phase error arithmetic unit which outputs a phase error value calculated using the outputs of the first, second and third phase mismatch detectors.