A contact portion, provided in an exposed surface of the treating section, treats a treated object by a transmitted ultrasonic vibration while intruding into the treated object toward an intruding direction from a state being in contact with the treated object. An index portion is disposed on an anti-intruding direction side with respect to the contact portion in the exposed surface. The index portion becomes an index indicating an intruding amount of the contact portion into the treated object toward the intruding direction. The index portion includes index surfaces arranged in the intruding direction, and each of the index surfaces has an angle relative to the intruding direction which is different from the angle of the adjacent index surface.