An apparatus and a method are provided for detecting N number of TX signals in a MIMO wireless communication system. The apparatus includes an RF processor, a channel estimator, and a signal detector. The RF processor converts signals, received through multiple antennas, into baseband signals. The channel estimator estimates channel information of the respective antennas by using the received signals. The signal detector arranges the baseband signals of the respective antennas on the basis of the channel information, calculates a threshold value of each stage, and selects symbols with a cumulative metric smaller than or equal to the threshold value as candidates at each stage, to detect a TX signal vector with N number of symbols.