The medical treatment instrument (1) according to the present invention can be opened and closed at the distal end of the elongated flexible insertion portion (2) and the insertion portion (2) for the purpose of achieving a high gripping force while reducing the diameter. A gripping part (3) supported by the insertion part (2), a drive part that is arranged at the proximal end of the insertion part (2) and generates power for driving the gripping part (3), and a power generated by the drive part (2). ), A power amplifying mechanism (5) for amplifying the power transmitted by the power transmitting member (4), and a gripping portion for the power amplified by the power amplifying mechanism (5). And a toggle mechanism (6) for amplifying and converting the power in the opening / closing direction of (3).
