An endoscopic treatment tool comprising: a sheath in which a lumen extending from a distal end to a proximal end of the sheath is formed; a treatment part (2, 4, 5) which is configured to be inserted into the lumen and is configured to protrude and retract from the distal end of the sheath, the treatment part (2, 4, 5) including: an elongated shaft including an insertion passage, and a stylet disposed in the insertion passage to be movable relative to the elongated shaft; a main manipulation part which is connected to a proximal end side of the sheath and allows the treatment part (2, 4, 5) to perform a first motion and a second motion, wherein the first motion is a motion of moving the stylet from a proximal end side toward a distal end side with respect to the elongated shaft, and the second motion is a motion of advancing and retracting the elongated shaft with the stylet; characterised by an auxiliary manipulation part which is disposed to be separate from the main manipulation part and is configured to perform the first motion of the treatment part (2, 4, 5) and to be incapable of performing the second motion; and a manipulation transmission member which has flexibility, connects the auxiliary manipulation part to the main manipulation part, and transmits a manipulation input of the auxiliary manipulation part with respect to the main manipulation part. a sheath in which a lumen extending from a distal end to a proximal end of the sheath is formed; a treatment part (2, 4, 5) which is configured to be inserted into the lumen and is configured to protrude and retract from the distal end of the sheath, the treatment part (2, 4, 5) including: an elongated shaft including an insertion passage, and a stylet disposed in the insertion passage to be movable relative to the elongated shaft; a main manipulation part which is connected to a proximal end side of the sheath and allows the treatment part (2, 4, 5) to perform a first motion and a second motion, wherein the first motion is a motion of moving the stylet from a proximal end side toward a distal end side with respect to the elongated shaft, and the second motion is a motion of advancing and retracting the elongated shaft with the stylet; characterised by an auxiliary manipulation part which is disposed to be separate from the main manipulation part and is configured to perform the first motion of the treatment part (2, 4, 5) and to be incapable of performing the second motion; and a manipulation transmission member which has flexibility, connects the auxiliary manipulation part to the main manipulation part, and transmits a manipulation input of the auxiliary manipulation part with respect to the main manipulation part. an elongated shaft including an insertion passage, and a stylet disposed in the insertion passage to be movable relative to the elongated shaft; a main manipulation part which is connected to a proximal end side of the sheath and allows the treatment part (2, 4, 5) to perform a first motion and a second motion, wherein the first motion is a motion of moving the stylet from a proximal end side toward a distal end side with respect to the elongated shaft, and the second motion is a motion of advancing and retracting the elongated shaft with the stylet; characterised by an auxiliary manipulation part which is disposed to be separate from the main manipulation part and is configured to perform the first motion of the treatment part (2, 4, 5) and to be incapable of performing the second motion; and a manipulation transmission member which has flexibility, connects the auxiliary manipulation part to the main manipulation part, and transmits a manipulation input of the auxiliary manipulation part with respect to the main manipulation part.