A MIMO antenna apparatus comprising: a radiating conductor(11, 21) having a plurality of slits (11a, 11b, 21a, 21b); a plurality of first feed points which are respectively provided on the radiating conductor, and the radiating conductor itself is adapted to be excited as a plurality of different first antennas (1a, 1 b) through the plurality of first feed points, respectively; a plurality of second feed points which are respectively provided at the plurality of slits (11a, 11b, 21a, 21b), and the plurality of slits are adapted to be excited as a plurality of second antennas (2a, 2b) through the plurality of second feed points, respectively; demodulation means for demodulating received radio signals by a MIMO, Multi-Input Multi-Output, scheme; a switching circuit including a plurality of switches (4a, 4b), each switch (4a, 4b) connected respectively to one of the first feed points and one of the second feed points, the switching circuit connecting one of the two feed points connected to each switch (4a, 4b), to the demodulation means; and control means for controlling each switch (4a, 4b) based on a first and a sec-ond signal measurement values of respective received radio signals of the two feed points connected to the switch, characterized in that, the control means is adapted to, when the first signal measurement value of a radio signal received by the ahtenna (1a, 2a) associated with one feed point currently connected to the demodulation means by a first switch, which is any one of the switches (4a, 4b), is less than or equal to a predetermined threshold value, the first switch to change the feed point connected to the demodulation means, to the other feed point connected to the first switch, and when the second signal measurement value received by the antenna associated with the other feed point connected to the first switch after the change of the feed point, is not higher than the first signal measurement value before the change of the feed point, control the first switch to change again the feed point connected to the demodulation means, to the one point. a radiating conductor(11, 21) having a plurality of slits (11a, 11b, 21a, 21b); a plurality of first feed points which are respectively provided on the radiating conductor, and the radiating conductor itself is adapted to be excited as a plurality of different first antennas (1a, 1 b) through the plurality of first feed points, respectively; a plurality of second feed points which are respectively provided at the plurality of slits (11a, 11b, 21a, 21b), and the plurality of slits are adapted to be excited as a plurality of second antennas (2a, 2b) through the plurality of second feed points, respectively; demodulation means for demodulating received radio signals by a MIMO, Multi-Input Multi-Output, scheme; a switching circuit including a plurality of switches (4a, 4b), each switch (4a, 4b) connected respectively to one of the first feed points and one of the second feed points, the switching circuit connecting one of the two feed points connected to each switch (4a, 4b), to the demodulation means; and control means for controlling each switch (4a, 4b) based on a first and a sec-ond signal measurement values of respective received radio signals of the two feed points connected to the switch, characterized in that, the control means is adapted to, when the first signal measurement value of a radio signal received by the ahtenna (1a, 2a) associated with one feed point currently connected to the demodulation means by a first switch, which is any one of the switches (4a, 4b), is less than or equal to a predetermined threshold value, the first switch to change the feed point connected to the demodulation means, to the other feed point connected to the first switch, and when the second signal measurement value received by the antenna associated with the other feed point connected to the first switch after the change of the feed point, is not higher than the first signal measurement value before the change of the feed point, control the first switch to change again the feed point connected to the demodulation means, to the one point.