PURPOSE: To prevent the saturation of the Doppler signal obtained from the reflected Doppler signal.

CONSTITUTION: A Doppler ultrasonic diagnostic device repeatedly emits ultrasonic beams into an organism and displays the bloodstream information in the organism based on the reflected echo signal obtained from the organism. This device is provided with a delay circuit 20 and a subtracter 21. The delay circuit 20 delays the Doppler signal obtained from the reflected echo signal by the cycle period of the ultrasonic beams. The subtracter 21 subtracts the delay result of the Doppler signal obtained previously by one cycle period from the Doppler signal.