A vibration transmitting member used with a clamp portion and configured to transmit vibration from an ultrasonic transducer, is extended from a proximal portion toward a distal portion, includes a ridge portion at the distal portion along a longitudinal axis extending from the proximal portion to the distal portion and located on a surface along an opening/closing direction in which the clamp portion is configured to move by turning, and is configured to transmit the vibration from the proximal portion to the distal portion thereof when the vibration is input to the proximal portion thereof. A thickness thereof along the opening/closing direction in which the clamp portion is configured to move by turning is smaller than a width of the distal portion thereof in a width direction perpendicular to the opening/closing direction.
