1. An apparatus for adjusting a white balance, the apparatus comprising: a camera unit; and a controller for controlling recognition of a facial image from an image captured by the camera unit and, when it is determined that the image has been captured with a complex light source based on a comparison between a white balance gain calculated based on a facial skin color of the recognized facial image and a white balance gain calculated based on a white balance scheme, for adjusting a white balance of the captured image based on a final white balance gain extracted by interpolating the white balance gain calculated based on the facial skin color of the recognized facial image and the white balance gain calculated based on the white balance scheme, wherein the controller compares a white balance gain (RGain Face , Bgain Face ) calculated based on the facial skin color and a white balance gain (RGain Normal , Bgain Normal ) calculated in the white balance scheme with a predetermined reference white balance gain (RGain Threshold , Bgain Threshold ) and determines that the image has been captured with a complex light source when RGain Face −RGain Normal >RGain Threshold and BGain Face −Bgain Normal <BGain Threshold .