ORNAMENT SUCH AS NECKLACE AND FASTENING DEVICE

PURPOSE:To upgrade decoration value of an ornament by providing a rotor having a circular wall and an elastic arm between a first internal frame having a mating protruding part fixed on a first external frame and a second internal frame having an opening fixed on a second external frame. CONSTITUTION:A mating protruding part 23 of a first internal frame 17 fixed on a first external frame is made to pierce a center hole 41 of a second internal frame 31 fixed on a second external frame 13 and is mated with center holes 45 and 61 respectively of a rotor 43 and a reinforcing body 55. Circular rings 71 and 73 are made to face each other askew at the upper parts of both the external frames. The face of the second internal frame 31 sticking out of a face 29 is matched with the face of the first internal frame 17 retreating from the joint face so that one of the first and second external frames can rotate with respect to the other without the disengagement thereof. When the first external frame is rotated by 90 deg. with respect to the second external frame 13, the rotor 43 turns by 90 deg. in the same direction so that the catching part 51 drops into cuts 37a-37d. At this time, the mating protruding part 23 can not be pulled out of the second internal frame, thereby making the first and second external frames mate with each other.