To substantially complete pressing movement of a trailing release part when a back face of a leading release part approaches a surrounding wall of a casing.

In the casing 33, one pair of rear and front winding parts 34 for winding looped both ends of an outer fastening cord 5 is provided, stopper bodies 35 approaching each of these winding parts 34 for sandwiching and locking the outer fastening cord 5 are swingably supported, and a release member 36 swinging both stopper bodies 35 in lock release directions is movably provided between the front and rear stopper bodies 35. The front and rear stopper bodies 35 have the release parts 40f and 40r abutting to the release member 36, and the release member 36 has uneven pressing faces F and R pressing the front and rear release parts 40f and 40r at different timings. A thickness of the leading release part 40f is provided thinner than the trailing release part 40r so that the back face of the leading release part 40f approaches the surrounding wall of the casing 33 when the pressing movement of the trailing release part 40r is substantially completed.