PROBLEM TO BE SOLVED: To reduce ultrasonic irradiation to parts other than a treatment part as much as possible.SOLUTION: When a user specifies a treatment range on a diagnostic image, a switch 12 selects a transmitter 16 for treatment, and thus strong ultrasonic waves for the treatment are sent out from a probe 10 into a living body. When the treatment operation is continued for the prescribed time, a control part 18 controls the switch 12 to select a transmitter 14 for diagnosing. Thus, the probe 10 generates ultrasonic beams for diagnosing, detects the echo, generates a diagnostic image, and inspects the position deviation of a treatment object part. In the inspection, the control part 18 compares the diagnostic image with a reference image (the diagnostic image when the treatment range is specified or the inspection immediately before is performed, for instance), and when a significant difference is detected between them, determines deviation occurrence, issues an alarm and urges the user to correct the position deviation. When the position deviation is corrected, the treatment can be restarted.
