A MIMO antenna apparatus receives a plurality of radio signals modulated and transmitted by a sender-side radio station apparatus using a MIMO (Multi-Input Multi-Output) communication method with a number of data streams and a modulation and demodulation method. The MIMO antenna apparatus includes a plurality of antenna elements, detection means, MIMO demodulation means, radio transmission means, and control means. The control means controls the sender-side radio station apparatus by making the radio transmission means transmit the control signal, and controlling the MIMO demodulation means, so as to change, based on the received signal levels and the signal quality, at least one of the number of data streams and the modulation and demodulation method for the MIMO communication method used by the sender-side radio station apparatus and the MIMO demodulation means.