An ultrasonic diagnosis and treatment system (1) has a thin tube which is capable of being inserted into a body cavity, and which has at its extreme end (14) an observing ultrasonic vibrator (24) for emitting ultrasonic waves for observation and a treating ultrasonic vibrator (20a, 20b) for emitting strong ultrasonic waves for treatment. Observation and treatment are performed by using ultrasonic waves. The system further includes a processing device for performing an operation other than the ultrasonic treatment at least on a region observed by using ultrasonic waves. A guide (51) for enabling the processing device to reach the region observed by using ultrasonic waves is provided on the thin tube. <IMAGE>
