PURPOSE: To easily and accurately examine and diagnose an objective region by providing an index means for confirming the arrangement position of the ultrasonic vibrator of an ultrasonic transmitting-receiving part or the position of an ultrasonic tomographic surface in an optical image.

CONSTITUTION: An index means 6 is provided to a part of the outer surface of the ultrasonic transmitting receiving part 2 at the leading end of an insert part 1 and confirms the arrangement position of the ultrasonic vibrator provided in the ultrasonic transmitting and receiving part 2 or the position of the ultrasonic slice surface S thereof in the optical image of the objective region of an examinee obtained by an optical observation part 3 and a mark is applied to the corresponding place in the arrangement direction thereof using appropriate paint. Therefore, a part of the ultrasonic transmitting-receiving part is seen in the optical image I due to the optical observation part 3 looked through an eyepiece part 5 and the index means 6 applied to the outer surface thereof is also observed and an operator can confirm the arrangement position of the ultrasonic vibrator of the ultrasonic transmitting-receiving part 2 or the position of the ultrasonic tomographic surface S. By this method, the objective region of the examinee can be examined and diagnosed easily and accurately.