An apparatus and method for localizing a sound source in a robot are provided. The apparatus includes a microphone unit implemented by one or more microphones, which picks up a sound from a three-dimensional space. The apparatus also includes a sound source localizer for determining a position of the sound source in accordance with Time-Difference of Arrivals (TDOAs) and a highest power of the sound picked up by the microphone unit. Thus, the robot can rapidly and accurately localize the sound source in the three-dimensional space with minimum dead space, using a minimum number of microphones.