In this paper, a new type of hot wire acoustic vector sensor based on Polyacrylonitrile base carbon fiber, as a sensing element is presented. The vector sensor employs two suspended carbon fiber with micro size diameter and millimeter length as a pair of hot wires that are close together with hundreds micron separation. V-I and V-R curves shows that temperature coefficient resistivity is negative for carbon fibers. Sensitivity of the sensor has been measured with different bias voltage that shows either the direction of the air flow or the acoustic source would be detected by comparing the output voltages of two suspended carbon fibers.