1. An apparatus for localizing a sound source in a robot, the apparatus comprising: a microphone unit comprising a plurality of microphones, wherein the microphone unit picks up a sound from a three-dimensional space; and a sound source localizer for determining a position of the sound source in the three-dimensional space in accordance with Time-Difference Of Arrivals (TDOAs) of the sound between the plurality of microphones and beamforming powers of respective points in the three-dimensional space in a direction of the sound source.