An adaptive antenna apparatus is provided with a total of four or more, even number N of antennas including a plurality of pairs of antennas each having a bidirectional characteristic. The N antennas are provided respectively at vertexes of a polygon of the same number as the number N of the antennas, so that each pair of antennas of the plurality of pairs of antennas opposes to each other. An adaptive control circuit takes an adaptive control over radio signals using one pair of antennas opposing to each other among the N antennas. In the adaptive antenna apparatus, the each pair of antennas is provided to oppose to each other so that axes of directions of main beams of the directional characteristics of the each pair of antennas substantially coincide with each other.