The voice box, or larynx, is the portion of the respiratory (breathing) tract containing the vocal cords which produce sound. It is located between the pharynx and the trachea. The larynx, also called the voice box, is a 2-inch-long, tube-shaped organ in the neck. We use the larynx when we breathe, talk, or swallow. Its outer wall of cartilage forms the area of the front of the neck referred to as the "Adam's apple."

Source: Medicine.net