A closure device includes a protruding member that is detachably provided at a distal end of a longitudinal member； a pair of grasping members that are turnable with respect to the protruding member； first and second linear members that are connected to the pair of grasping members； and a holding portion that has an action portion for applying a force in a direction in which the pair of grasping members approach the protruding member and is detachably provided at a distal end of the longitudinal member.
