PURPOSE: To obtain the device capable of measuring the speed of blood in a deep part in the interior of the body at high speed in a ratio of signals to noises superior to another ratio of the other signals to the other noises obtained in the case where a pulse which is not coded is used.

CONSTITUTION: The supersonic wave high speed flow measurement device is provided with a modulator 40 for producing at least two coded. pulses separated for a preset delay time alone and a transducer 80 for transmitting the two coded pulses to a measurement-intended object. In addition, a receiver for receiving an echo signal returned from the measurement-intended object, decoders 110, 120 for generating at least two decoding signals separated for a preset delay time alone and a corelation device 200 for mutually corelating the two decoding signal and outputting the speed distribution of the measurement- intended object are equipped.