To provide an operating portion which allows a bending treatment instrument to be inserted into an endoscope channel and bendably operated smoothly through intuition. The present invention provides an operating portion connected with a device wire and a plurality of bending wires and used to operate the treatment instrument and bend a freely bendable, bending treatment instrument, where the device wire is connected to a treatment instrument provided at a distal end of the bending treatment instrument and is used to operate the treatment instrument and the plurality of bending wires is used to bend the bending treatment instrument, the operating portion including: an operating portion body； a guide unit penetrated by the device wire； a bending wire pulling unit connected with the bending wires and swingably assembled onto the guide unit； and a grip portion connected with the device wire and configured to be reciprocable in an axial direction of the bending wire pulling unit.
