An adaptive array transceiver wherein: received baseband signals from antennas (111 to 11Q) are multiplied by weight coefficients to effect linear synthesization, judgment signals are lagged by one symbol and multiplied by feedback filter constants (Wb*) to produce an intersymbol interference; the intersymbol interference is subtracted from the linearly synthesized output (Y(i)), and the resultant output is subjected to sign judgment, and the sign judgment signal is outputted; and an error signal (e(i)) representing the difference between the input of a judging unit (17) and the judgment signal is generated, and a parameter estimating section (71) estimates weighting coefficients (W1* to WQ*) and the feedback filter coefficient (Wb*) so that the square of the error signal (e(i)) is minimized. On the transmission side, the transmission signal is lagged by one T and multiplied by Wb*, and the intersymbol interference is subtracted from the transmission signal to give distortion to the signal. The resultant outputs are multiplied by W1* to WQ*, respectively, to generate transmission baseband signals to the antennas (111 to 11Q).