Ultrasound oscillation can be propagated to a distal end of an elongated probe. A cross-sectional surface of the probe is perpendicular to the length of the probe, and has to the same shape as a shape of a cross-sectional surface of an anchor. The probe is configured to forma bottomed hole in a bone for placing the anchor and the shape of its cross-sectional surface can prevent rotation of the anchor in the bottomed hole. An area of the cross-sectional surface of the probe at the distal end can be larger than an area of a cross-sectional surface of the probe at a proximal end. The distal end of the probe includes a treatment portion that extends outward from a center of the proximal end of the probe in a first direction perpendicular to the longitudinal direction and in a second direction different from the first direction.