An adaptive array antenna includes an array antenna having a plurality of antenna elements, and a plurality of reception units for receiving reception signals from the respective antenna elements, multiplying the reception signals by respective reception weighting coefficients, and outputting the weighted reception signals. The adaptive array antenna also includes a plurality of transmission units for multiplying transmission signals by respective transmission weighting coefficients and then transmitting the weighted transmission signals from the respective antenna elements, and a reference signal transmission unit for transmitting a predetermined reference signal. Further, the adaptive array antenna includes a signal component separation unit for separating each of the reception signals into a correlated signal component correlated with the reference signal and an uncorrelated signal component uncorrelated with the reference signal, and a weighting coefficient correction unit for updating each of the transmission weighting coefficients on the basis of the corresponding correlated signal component.