An endoscopic treatment instrument includes a pressing tube with an insertion lumen; a clip main body that has a first arm being inserted into the insertion lumen; a second arm fixed to the pressing tube; and an operation wire connected to the clip main body to move it with respect to the pressing tube, wherein the first arm approaches the second arm while being moved to a proximal end side of the pressing tube, in an initial state before the clip main body is pulled by the operation wire, a position of a distal end of the first arm is more distal than a position of a distal end of the second arm, and the distal end of the first arm is approaches the distal end portion of the second arm when the clip main body is pulled to the proximal end side of the pressing tube.