The present invention relates to an apparatus and a method for performing beamforming using multiple antennas in a wireless AV system. The present specification discloses a wireless data transmission apparatus comprising: a plurality of transmission antennas; a communication circuit for performing a MIMO beamforming procedure on the basis of an individual transmission sector sweep for each of the plurality of transmission antennas during a data transmission interval within a beacon interval, and transmitting a physical layer protocol data unit (PPDU) frame to a wireless data reception apparatus through the plurality of transmission antennas; and a processor connected to the communication circuit, and configured to generate AV data to be transmitted through the PPDU frame and provide the generated AV data to the communication circuit. The present invention can reduce time required for MIMO beamforming while minimizing training of an excessive sector combination in a communication procedure or information related to the MIMO beamforming in a wireless AV system, and maintain the reliability of the system by using an optimum sector combination.