PURPOSE: To simplify the structure of a rotating direction control mechanism by fitting a cylindrical shaft body into each end side of first and second coil springs while providing a controlling external force operating portion which is rotatable in the direction of unwinding the coil spring by external force on the free end side of each of the coil springs.

CONSTITUTION: By applying an external force to the controlling external force operating portion 3b of a first coil spring 3, as it is unwindingly operated, the power transmitting relation between the first coil spring 3 and a cylindrical shaft body 5 is removed. Therefore, a second coil spring 4 determines the behavior of the cylindrical shaft body 5. Hence, in this case, the rotation in the direction 1 is free whereas the rotation in the other direction is prevented by the reduced diameter of the second coil spring 4. Also, by applying an external force to only the controlling external force operating portion 4b of the second coil spring 4 unwindingly operating same, the rotation in the other direction of the cylindrical shaft body 5 is free while preventing the rotation in the direction 1 by the reduced diameter of the first coil spring 3.