An ultrasonic probe that transmits ultrasonic vibrations from the proximal end to the distal end includes an outer peripheral portion provided along the longitudinal axis and a vertical plane perpendicular to the longitudinal axis, and the surface is continuous with the distal end of the outer peripheral portion serving as an outer edge. A continuous surface portion provided in a state of Cavitation occurs when the ultrasonic vibration is transmitted to the continuous surface portion. In addition, the ultrasonic probe includes a passage defining surface that defines a suction passage in the interior along the longitudinal axis from the proximal end to a portion on the proximal direction side from the surface continuous portion, and from the outer peripheral portion to the suction passage. And a hole defining surface that defines the suction hole to be extended.基端から先端へ超音波振動を伝達する超音波プローブは、長手軸に沿って設けられる外周部と、長手軸に対して垂直な垂直平面を備え、前記外周部の先端を外縁として表面が連続する状態で設けられる表面連続部とを備える。前記表面連続部に、前記超音波振動が伝達されることによりキャビテーションが発生する。また、超音波プローブは、前記基端から前記表面連続部より基端方向側の部位まで、前記長手軸に沿って内部に吸引通路を規定する通路規定面と、前記外周部から前記吸引通路まで延設される吸引孔を規定する孔規定面とを備える。
