PROBLEM TO BE SOLVED: To provide a clip device capable of properly controlling the opening/closing of a clip even if a difference in a path length between a sheath and an operation wire occurs.SOLUTION: A base end part 210 of the clip 20 is provided on the more proximal side than an arm portion and is connected with a connection portion 30. A tightening portion 30 sheaths a body and is moved to the distal side relatively to the body to tighten and close the arm portion. The clip transits to a first state where the tightening portion releasably tightens the arm portion to reversibly close the arm portion and a second state where the arm portion moves to the more distal side than the first state relatively to the tightening portion 24 to open the arm portion. The sheath 420 restricts the backward movement of the tightening portion. The base end part 210 or the connection portion has a margin for the forward/backward movement of the connection portion relatively to the base end part when they are connected to each other. When the operation wire 440 moves forward/backward, the connection portion freely moves relatively to the base end part, so that it is suppressed that the clip transits from the first state to the second state.
