PURPOSE: To simplify a structure, by constituting a specimen stand driving apparatus as a common drive part consisting of a writing drive part and a feed drive part and providing a clutch means for making both drive parts selectively connectable and disconnectable.

CONSTITUTION: When a specimen is arranged on a specimen stand and an ultrasonic acoustic lens is reciprocally moved to an X-direction at a high speed by an exciting apparatus, the rotation of a geared motor 46 is transmitted to the writing driving shaft 38 of a gear box 36 through an electromagnetic clutch 45 and an output shaft 37 is rotated through bevel gears 42a, 41. This rotation is transmitted to a ball screw 34 for driving in a Y-direction and the specimen stand slowly moves to the Y-direction. When the specimen is moved to a necessary place, a clutch 45 is disengaged and a pulse motor 48 for a Y-direction is rotated and the feed drive shaft 39 of the gear box 36 is driven through a clutch 47 to enable Y-direction feed. Further, a pulse motor 35 for an X-direction is rotated and this rotation is transmitted to a ball screw 23 for driving in the X-direction to enable the feed of the specimen stand to the X-direction.