This endoscopic treatment instrument is provided with: a clip unit provided with a clip main body, which has a first arm and a second arm, a restraining tube, which causes the first arm and second arm to approach each other as the clip main body moves to the base end side, a locking section, and a locking subject section； a linear member linked to the clip unit； a sheath section into which the linear member is inserted in a manner so as to be able to advance and retract； and a breaking mechanism connected to the base end of the linear member. The breaking mechanism has: a first support member； a second support member； and a planned-breakage member that is connected to the first support member and the second support member and of which the tensile strength with respect to tensioning force in the direction of the axis line of the linear member is lower than that of the first support member and the second support member. The force necessary to break the planned-breakage member is set higher than the force necessary to move the clip main body, which is housed in the restraining tube, in a manner so that the locking subject section traverses the locking section to be positioned at the base end side of the locking section.L'instrument de traitement endoscopique de l'invention est équipé : d'une unité de pince à son tour équipée d'un corps principal de pince possédant une première ainsi qu'une seconde partie bras, d'un tube de pression qui rapproche lesdites première et seconde parties bras selon les déplacements côté extrémité de base dudit corps principal de pince, d'une partie verrouillage, et d'une partie à verrouiller ； d'un élément linéaire couplé à ladite unité de pince ； d'une partie gaine dans laquelle ledit élément linéaire est inséré de manière à pouvoir avancer et reculer ； et d'un mécanisme de rupture connecté à une partie extrémité de base dudit élément linéaire. Ledit mécanisme de rupture possède : un premier élément support ； un second élément support ； et
