PURPOSE: To precisely inject medicine into the focus of ultrasonic waves set on the part to be treated by attaching a pressure receiving part at the top of a piercing needle to make it recognize that the top of the needle has reached the part to be treated when the ultrasonic signal received at the pressure receiv ing part is judged to be larger than the prescribed value.

CONSTITUTION: The ultrasonic diagnosis device 9 takes a picture near the part 5 to be treated, and the picture is shown on the screen of the monitor 10. The applicator 4 is adjusted so that the focus 6 of the applicator is placed on the part 5 to be treated. Then ultrasonic waves for deep examination are generated from the vibrator 2, and the piercing needle 8 is pierced into the part 5 to be treated. The piezoelectric film 20 attached at the top of the needle 8 receives the ultrasonic waves for deep examination, and the receiving signal is inputted to the echo level judgement circuit 13. When the receiving signal is larger than the prescribed marginal value set by the marginal value prescription circuit 14, it is judged that the needle has reached the part to be treated, and then, medicine is to be supplied to the part 5 to be treated through the needle 8 by operating the syringe 7.