The present disclosure relates to a multi input and multi output antenna apparatus. The multi input and multi output antenna apparatus may include: an antenna board having a plurality of antenna elements arranged on a front surface thereof; and a transmitting/receiving module board having a plurality of first heat generation elements provided on a front surface thereof and a plurality of second heat generation elements provided on a rear surface thereof, and disposed to have a separation space from the antenna board. The heat generated from the plurality of first heat generation elements may be radiated to the front of the transmitting/receiving module board, and the heat generated from the plurality of second heat generation elements may be radiated to the rear of the transmitting/receiving module board.