PURPOSE: To simultaneously execute observation and treatment of a diseased part and to prevent the degradation of an ultrasonic probe by providing a heating means, which is provided in the tip part of the main body of the probe, for the diseased part, ultrasonic detecting means and cooling means for the ultrasonic detecting means.

CONSTITUTION: A main body 1 of the probe is inserted to a void and an ultrasonic probe 11 is moved in an axial direction and a rotational direction in the main body 1 of the probe. Then, the diseased part is searched by an ultrasonic probe 10 and a tomographic image is projected and observed on an ultrasonic observing device. An inserting position is adjusted so that microliquid can arrive at a tumor position. Afterwards, a microwave is discharged toward the diseased part and thermal treatment is executed to the diseased part. In such a case, the temperature of the diseased part and surrounding parts is detected by temperature sensing elements 8a, 8b, 8c... and a signal is sent to a temperature measuring instrument 7. Then, the diseased part is automatically adjusted to a temperature set in advance. Simultaneously, a temperature sensing element 9 detects a temperature near the ultrasonic probe 10 and sends a signal to the temperature measuring instrument 7. When the detected temperature is more than the set temperature, a roller pump 15 is operated and the probe 10 is cooled by cooling water 17.