There is disclosed an embodiment for providing a three dimensional color Doppler image. An ultrasound data acquisition unit may transmit and receive ultrasound signals to and from a target object to output ultrasound data. A processor may form Doppler signals including power information of the target object and at least one of direction information and velocity information of the target object by using the ultrasound data. The processor may further form a three dimensional Doppler mode image representing the power information and at least one of the direction information and the velocity information by using the Doppler signals.
