An ultrasonic probe includes a hook curved relative to a probe main body in a first perpendicular direction and forming a part of a distal surface, and a first base surface extending toward a proximal direction from a hook proximal end and serving as a base plane of the hook. The ultrasonic probe includes a protrusion protruding toward a second perpendicular direction with a second base surface, which is directed in a second perpendicular direction opposite to the first perpendicular direction, being as a base plane and extending toward both the proximal direction and a distal direction from a reference position located on a section, which passes through the hook proximal end and which is perpendicular to a longitudinal axis.