Ultrasonic imaging apparatus using pulsed Doppler signal

In an ultrasonic imaging apparatus using pulsed Doppler signal, the amplitudes of the reflected echo signals are decreased in accordance with a depth of the body. The echo signals received by the transducer are detected in the phase detectors in such a manner that the echo signals are mixed with the reference signals whose amplitudes vary in accordance with the distances between the portions in the body and the transducer, over which the reflected echo signals are propagated.