An endoscope treatment tool comprising: a clip unit having a clip main body which includes first and second arm portions (12, 13), a pressing tube which is formed in a tube shape to be capable of accommodating the clip main body and provided to make a distal end of the first arm portion and a distal end of the second arm portion to approach to each other as the clip main body is moved toward a proximal end side of the pressing tube, a locking portion which protrudes from an inner circumferential surface of a proximal end of the pressing tube, and a locked portion (16, 17, 21, 22) which protrudes from the clip main body; a linear member having a distal end portion connected to the clip unit and provided to manipulate the clip main body by being advanced and retracted; an endoscope comprising a channel; a sheath portion being inserted into the channel of the endoscope, wherein the linear member is inserted into the sheath portion so that the linear member is advanceable and retractable; and a manipulation portion having a manipulation portion main body connected to a proximal end portion of the sheath portion, a slider configured to be movable relative to the manipulation portion main body, and a fracture mechanism configured to connect a proximal end portion of the linear member and the slider, the manipulation portion being configured to be manipulated at a proximal end side of the channel when the sheath portion is inserted into the channel, wherein the fracture mechanism includes: a first support member connected to the proximal end portion of the linear member, a second support member disposed on a proximal end side of the first support member and connected to the slider, and a fracturable member disposed between the first support member and the second support member so as to connect the first support member and the second support member, the fracturable member being configured such that fracture strength of the fracturable member against a tensile force applied to pull the linear member in an axial line direction is lower than the first and second support members (80, 81), wherein a force necessary to make the fracturable member to be fractured is set higher than a force necessary to move the clip main body accommodated in the pressing tube so that the locked portion (16, 17, 21, 22) is located on a proximal end side of the locking portion beyond the locking portion. a clip unit having a clip main body which includes first and second arm portions (12, 13), a pressing tube which is formed in a tube shape to be capable of accommodating the clip main body and provided to make a distal end of the first arm portion and a distal end of the second arm portion to approach to each other as the clip main body is moved toward a proximal end side of the pressing tube, a locking portion which protrudes from an inner circumferential surface of a proximal end of the pressing tube, and a locked portion (16, 17, 21, 22) which protrudes from the clip main body; a linear member having a distal end portion connected to the clip unit and provided to manipulate the clip main body by being advanced and retracted; an endoscope comprising a channel; a sheath portion being inserted into the channel of the endoscope, wherein the linear member is inserted into the sheath portion so that the linear member is advanceable and retractable; and a manipulation portion having a manipulation portion main body connected to a proximal end portion of the sheath portion, a slider configured to be movable relative to the manipulation portion main body, and a fracture mechanism configured to connect a proximal end portion of the linear member and the slider, the manipulation portion being configured to be manipulated at a proximal end side of the channel when the sheath portion is inserted into the channel, wherein the fracture mechanism includes: a first support member connected to the proximal end portion of the linear member, a second support member disposed on a proximal end side of the first support member and connected to the slider, and a fracturable member disposed between the first support member and the second support member so as to connect the first support member and the second support member, the fracturable member being configured such that fracture strength of the fracturable member against a tensile force applied to pull the linear member in an axial line direction is lower than the first and second support members (80, 81), a first support member connected to the proximal end portion of the linear member, a second support member disposed on a proximal end side of the first support member and connected to the slider, and a fracturable member disposed between the first support member and the second support member so as to connect the first support member and the second support member, the fracturable member being configured such that fracture strength of the fracturable member against a tensile force applied to pull the linear member in an axial line direction is lower than the first and second support members (80, 81), wherein a force necessary to make the fracturable member to be fractured is set higher than a force necessary to move the clip main body accommodated in the pressing tube so that the locked portion (16, 17, 21, 22) is located on a proximal end side of the locking portion beyond the locking portion.