PURPOSE: To measure the distance between specified portions in the organism with higher accuracy by processing output signals of a signal reception delay line by each signal to arrange according to the order of arrayed oscillators and by measuring the distance between specified portions according to the waveform of the reflected echoes to convert the value into a conversion distance in the organism.

CONSTITUTION: In the measurement of the diameter of a blood vessel 10, etc., a drive waveform is applied to plural arrayed oscillators 11 via a signal transfer delay line 12, the waveform are generated from the oscillators 11, and reflected pulse waves that are reflected at a blood vessel 10 are received by the oscillators 11. The electric signals are input to an adder 14 via a signal reception delay line 13 to create one-line reflection signals, and the output of each signal reception delay line is input to a multi signal processing circuit 20 to be processed with a logarithmic compression, detection, STC, etc., and stored in a buffer memory 22. At DSC 23, signals that have been brilliance-modulated to specified positions of the ultrasonic image are displayed according to the order of the arrayed oscillators 11, the distance between specified two portions is measured using the electronic caliper function, and the value is converted into a conversion distance in the organism.