An endoscopic treatment tool, comprising: a needle tube in which a needle tube insertion passage extending from a distal end to a proximal end of the needle tube is formed; a stylet which is disposed to move freely in the needle tube insertion passage; a main manipulation part which is connected to a proximal end side of the needle tube, the main manipulation part supporting the stylet; a manipulation transmission member which has flexibility and the manipulation transmission member is connected to the stylet; an auxiliary manipulation part which includes a handle fixed to a proximal end portion of the manipulation transmission member, wherein the manipulation transmission member is configured to advance while rotating in accordance with a manipulation of the handle; a sheath in which a lumen extending from a distal end to a proximal end of the sheath is formed, wherein the needle tube is inserted into the lumen; a stylet proximal end member which is fixed to a proximal end portion of the stylet; and an engagement part which protrudes from an outer peripheral surface of the stylet proximal end member; wherein the main manipulation part includes a first cam tube which includes an insertion passage formed along a longitudinal axis, and in which a first guide passage is formed in a helical shape around a central axis of the insertion passage of the first cam tube, and wherein the stylet proximal end member is inserted into the insertion passage of the first cam tube, so that the stylet is capable of advancing while rotating by being supported by the main manipulation part, and so that the endoscopic treatment tool is configured such that, when the manipulation transmission member is advanced while being rotated by the auxiliary manipulation part, the engagement part moves while being engaged with the first guide passage, so that the stylet rotates around a central axis of the sheath while advancing, and wherein the auxiliary manipulation part includes a second cam tube in which a second guide passage is formed in a helical shape at a same helical pitch and in a same rotational direction as the first guide passage, and the handle includes a projection which is engaged with the second guide passage, so that the manipulation transmission member is configured to advance while rotating by the projection moving while the projection is engaged with the second guide passage. a needle tube in which a needle tube insertion passage extending from a distal end to a proximal end of the needle tube is formed; a stylet which is disposed to move freely in the needle tube insertion passage; a main manipulation part which is connected to a proximal end side of the needle tube, the main manipulation part supporting the stylet; a manipulation transmission member which has flexibility and the manipulation transmission member is connected to the stylet; an auxiliary manipulation part which includes a handle fixed to a proximal end portion of the manipulation transmission member, wherein the manipulation transmission member is configured to advance while rotating in accordance with a manipulation of the handle; a sheath in which a lumen extending from a distal end to a proximal end of the sheath is formed, wherein the needle tube is inserted into the lumen; a stylet proximal end member which is fixed to a proximal end portion of the stylet; and an engagement part which protrudes from an outer peripheral surface of the stylet proximal end member; wherein the main manipulation part includes a first cam tube which includes an insertion passage formed along a longitudinal axis, and in which a first guide passage is formed in a helical shape around a central axis of the insertion passage of the first cam tube, and wherein the stylet proximal end member is inserted into the insertion passage of the first cam tube, so that the stylet is capable of advancing while rotating by being supported by the main manipulation part, and so that the endoscopic treatment tool is configured such that, when the manipulation transmission member is advanced while being rotated by the auxiliary manipulation part, the engagement part moves while being engaged with the first guide passage, so that the stylet rotates around a central axis of the sheath while advancing, and wherein the auxiliary manipulation part includes a second cam tube in which a second guide passage is formed in a helical shape at a same helical pitch and in a same rotational direction as the first guide passage, and the handle includes a projection which is engaged with the second guide passage, so that the manipulation transmission member is configured to advance while rotating by the projection moving while the projection is engaged with the second guide passage.