An apparatus and a method of automatically setting a sound mode of a broadcast receiver without a user setting, using a vertical blanking interval. The apparatus includes a vertical blanking interval signal decoder, a memory, a sound decoder, and a system control unit. The vertical blanking interval signal decoder decodes a signal included in the vertical blanking interval of a received broadcasting signal. The memory stores one or more sound band control signals with respect to a plurality of sound modes. The sound decoder controls a sound band of an audio signal included in the received broadcasting signal and outputs the audio signal whose sound band is controlled. The system control unit detects a sound band control signal from the memory based on sound mode data included in data output from the vertical blanking interval signal decoder and controls the sound decoder using the detected sound band control signal.