PROBLEM TO BE SOLVED: To provide a vibration transmission member capable of securing stress resistance against grip without affecting treatment performance even when the vibration transmission member is downsized.SOLUTION: A vibration transmission member which is used together with a clamp part having a pressing pad and can transmit vibrations from an ultrasonic transducer has: a treatment surface which faces the clamp part and includes a contact surface the pressing pad is in contact with and a thick part which is provided on the back surface opposite the treatment surface with a longitudinal shaft extending from a base end part to a distal end part of the pressing pad in between and is formed thicker gradually with respect to the longitudinal shaft as it goes from the end side away from the base end position along the longitudinal shaft of the contact surface toward the base end side away from the distal end position.SELECTED DRAWING: Figure 7A【課題】 振動伝達部材の小型化を進めた場合であっても、処置性に影響を与えることなく、把持に対する応力耐性を確保することが可能な振動伝達部材を提供する。【解決手段】 押圧パッドを有するクランプ部とともに使用され、超音波トランスデューサからの振動を伝達可能な振動伝達部材は、前記クランプ部に対向し、前記押圧パッドが当接する当接面を含む処置面と、前記押圧パッドの基端部から先端部に向かって延伸した長手軸を挟んで前記処置面と反対側の背面に設けられ、前記当接面のうち前記長手軸に沿った基端位置よりも先端側から、前記基端位置よりも基端側に向かうにつれて前記長手軸に対して徐々に肉厚になるように形成された肉厚部とを有する。【選択図】図7A
