A closure device comprising: a first longitudinal member which extends along a longitudinal axis; a second longitudinal member which extends along the longitudinal axis so as to be movable relative to the first longitudinal member; a protruding member which is detachably provided at a distal end of the first longitudinal member; a pair of grasping members which comprises a first grasping member and a second grasping member each of which includes a distal end portion and an intermediate portion, wherein the distal end portion is capable of grasping tissue between the pair of grasping members (43A, 43B) and the protruding member, and the intermediate portion is turnably supported around a turning shaft provided at the protruding member, a first operating portion which is provided at a proximal end of the first longitudinal member, and which is configured to operate the first grasping member; a second operating portion which is provided at a proximal end of the first longitudinal member, and which is configured to operate the second grasping member independently from the first grasping member; a first linear member which extends along the longitudinal axis, wherein a distal end of the first linear member is connected to the first grasping member and a proximal end of the first linear member is connected to the first operating portion; a second linear member which extends along the longitudinal axis so as to be movable relative to the first linear member, wherein a distal end of the second linear member is connected to the second grasping member and a proximal end of the second linear member is connected to the second operating portion; and a holding portion that has an action portion for applying a force in a direction in which a proximal end of the first grasping member and a proximal end of the second grasping member approach the protruding member, is provided at a distal end of the second longitudinal member, and is capable of being removed from the distal end of the second longitudinal member together with the pair of grasping members (43A, 43B). a first longitudinal member which extends along a longitudinal axis; a second longitudinal member which extends along the longitudinal axis so as to be movable relative to the first longitudinal member; a protruding member which is detachably provided at a distal end of the first longitudinal member; a pair of grasping members which comprises a first grasping member and a second grasping member each of which includes a distal end portion and an intermediate portion, wherein the distal end portion is capable of grasping tissue between the pair of grasping members (43A, 43B) and the protruding member, and the intermediate portion is turnably supported around a turning shaft provided at the protruding member, a first operating portion which is provided at a proximal end of the first longitudinal member, and which is configured to operate the first grasping member; a second operating portion which is provided at a proximal end of the first longitudinal member, and which is configured to operate the second grasping member independently from the first grasping member; a first linear member which extends along the longitudinal axis, wherein a distal end of the first linear member is connected to the first grasping member and a proximal end of the first linear member is connected to the first operating portion; a second linear member which extends along the longitudinal axis so as to be movable relative to the first linear member, wherein a distal end of the second linear member is connected to the second grasping member and a proximal end of the second linear member is connected to the second operating portion; and a holding portion that has an action portion for applying a force in a direction in which a proximal end of the first grasping member and a proximal end of the second grasping member approach the protruding member, is provided at a distal end of the second longitudinal member, and is capable of being removed from the distal end of the second longitudinal member together with the pair of grasping members (43A, 43B).