Provided is a treatment instrument for endoscope, which facilitates the work of inserting the treatment instrument for endoscope from the proximal end side of a guidewire, and the work of removing the treatment instrument for endoscope, which has good handling properties, and which can be easily interchanged with other treatment instruments for endoscope. A balloon (2) is provided at the distal end of the catheter tube (5) that constitutes part of the treatment instrument for endoscope, and a distal-side wire insertion hole (10b) that connects to the main lumen (10) is formed on the distal end of the catheter tube (5). On the proximal side of the balloon (2), at a position partway along the catheter tube (5) in the longitudinal direction, a proximal-side wire insertion hole (10a) that is connected to the main lumen (10) is formed, and a tube-shaped member (30) is inserted towards the distal end direction of the main lumen (10) from the proximal-side wire insertion hole (10a). The peripheral edge of the proximal end opening (30a) of the tube-shaped member (30) is joined to the peripheral edge of the proximal-side wire insertion hole (10a).