To provide a high-frequency treatment instrument for endoscopes capable of safely incising an intended site by accurately directing an elongate electrode exposure portion equivalent to the cutting edge of a tip electrode to a targeting incision object position, having a simple mechanism and preventing easy occurrence of malfunction.

The tip electrode 2 is formed of a pair of spring wire rods 20 disposed in an inverse-tapered shape, an electric insulating coating 25 is applied to the surfaces of the pair of spring wire rods 20 which are opened/closed by the elasticity of themselves with extracting/retracting operations relative to the distal end of a flexible sheath 1, and the electrode exposure portion 26 non-covered with the electric insulating coating 25 is formed elongate in axial direction at least in one of the surface in closing-direction and the surface in opening-direction of at least one of the pair of spring wire rods 20.