Patent ID: 7731714

Claim:
An instrument for an endoscope comprising: an insulative insertion section adapted to be inserted in a channel of an endoscope and having flexibility; a tubular first electrode section arranged at a distal end of the insertion section and on which an insertion hole is formed along the axis of the insertion section; a conductive electric wire inserted in the insertion section so as to be freely movable forwards and backwards; a control section arranged on the proximal end side of the insertion section and controlling forward/backward movement of the electric wire along the axial direction; a rod-shaped second electrode section connected to a distal end of the electric wire and inserted so as to be freely movable forwards and backwards inside the insertion hole; an external connecting section electrically connected to a proximal end side of the electric wire and applying external currents with predetermined frequencies to the electric wire and the second electrode section; a recess formed at the distal end of the first electrode section so as to surround the periphery of the opening of the insertion hole; and a salient arranged at the distal end of the second electrode section and which extends in the direction perpendicular to the axial direction, wherein the second electrode section protrudes from and retracts into the distal end of the first electrode section in response to the movement control by the control section, and also electrically connects with the first electrode section when retracted into the first electrode section when retracted into the first electrode section, and the salient is contained in the recess when the second electrode section retracts into the first electrode section.