PURPOSE: To apply the uniform tightening force on the whole periphery of a jointed pipe, by installing a pair of tightening fitting bodies engaged at both the end parts of the tightening line wound in a spiral shape and a screwing means for tightening both the tightening fitting bodies, as for a clamping device suitable for clamping the joint part between the exhaust pipes of an automobile.

CONSTITUTION: When the exhaust pipes 5 and 6 for automobile are connected, the downstream side exhaust pipe 6 is fitted with the exhaust pipe 5 on the upstream side, and the spiral-shaped tightening life 1 of a clamping device 4 is fitted on the outer periphery. The tightening line 1 is formed by winding a spring steel in a spiral form in the nearly 1.7 turns, and both the ends of the tightening line 1 are inserted into a hole 2d opened on the slide curved surfaces 2a of a pair of tightening fitting bodies 2, and the top end is caulked, and engaged with the slidable curved surface 2a by forming a head part 1a. Then, both the seat surfaces 2b and 2b are shifted, sliding along the outer peripheral surface (outer peripheral line) of the spiral-shaped tightening line 1 by tightening the nut 3B of a screwing means 3, and both the exhaust pipes 5 and 6 are tighetened by the tightening line 1 in a contracted diameter state.