PURPOSE: To securely connect two retaining bands by comprising a connecting device both of a thin base plate and of claws spaced at a distance so as to be erected from the base plate part, and after these claws have been pierced through lockedly engaging holes, by forming them so as to be engaged with the lockedly engaging holes.

CONSTITUTION: A connecting device 10 comprises a thin base plate part 11 and claws 12, 12 which are formed at a distance so as to be erected from the base plate part 11. After having been pieced through lockedly engaging holes 7 provided to the base parts 2 of retaining bands 1, the claws 12 are bent toward the base plate 11 side so as to connect two retaining bands 1, 1. Further, at least a pair of second claws 13 are provided on both sides of the connecting device 10 so that both ends of the connecting part can be securely brought into close contact, and the claws 13 are bent so that the base part 2 of the retaining band 1 can be brought into close contact with the base plate 11 of the connecting device 10. As mentioned above, since two retaining bands 1, 1 can be connected to each other, in case where the retaining band has become short because of breakage or the like, it can be easily connected to the other retaining band.