PROBLEM TO BE SOLVED: To improve the operability of a high frequency treatment instrument for an endoscope.SOLUTION: A support member 32 pivotally supporting a pair of rotatable electrodes 31a and 31b is attached to a fixing member 35, provided at the distal end of an outer sheath 11, so as to be rotatable around the axis of the support member 32. A conductive drive wire 13 is inserted into an insulative inner sheath 12, and further inserted into an outer sheath 11. The distal end of the drive wire 13 is connected to the electrodes 31a and 31b via a pair of linear members 17a and 17b. The electrode 31a is electrically connected to the drive wire 13 via the linear member 17a. The electrode 31b is electrically connected to a wire inserted between the outer and inner sheathes 11 and 12 via the fixing member 35, a C-ring 34, and a return electrode provided on the support member 32.
