PURPOSE: To realize the title apparatus having well-balanced characteristics by inputting a plurality of inputted receiving signals to a plurality of signal separation means and separating the same into two groups of receiving signal at both terminals of a delay means by a change-over means and further performing the phasing addition thereof by two delay addition means.

CONSTITUTION: The ultrasonic wave reflected from the reflecting point in an examinee to be returned is received by a array transducer 2 to be converted to an electric signal which is, in turn, inputted to a receiving circuit 3. The receiving circuit 3 applies processing such as variable aperture or dynamic focus processing to the input signal and amplifies the signal to send the same to a beam splitter 11. The signal of each channel is inputted to a circuit at every channel in the beam splitter 11. This input signal is connected to the predetermined tap of a delay line 17 by a switch 18 to be separated into a signal advancing to the left and a signal advancing to the right and the signals advancing to the left and the right are respectively delayed by τ1, τ2 to be amplified by amplifiers 19, 20 and respectively inputted to delay addition circuits 12A, 12B to be subjected to phasing addition and amplified by amplifiers 16A, 16B to output echoes A, B.