A bracelet type fastening device for releasably affixing the ends of a bracelet type item to each other to secure the item on a part of the body of a wearer comprises a first fastening member pivotally affixed to a first end of a bracelet type item and having a semicircular support part of predetermined diameter and a catch pin affixed to the support part and extending diametrically thereacross. A second fastening member is pivotally affixed to a second end of the bracelet type item and has a spherical hook member having a diameter smaller than the predetermined diameter and a slot formed radially therein for accommodating the pin of the first fastening member. The slot extends in a plane inclined at a predetermined angle with a central plane of the second fastening member and opens toward the item. The second fastening member on the part of the body of a wearer is pivotable relative to the item to an insertion and removal position in which the hook member is movable into and out of the support part of the first fastening member with the pin of the first fastening member being simultaneously moved into and out of the slot of the hook member. The second fastening member is further pivotable relative to the item to a secure position in which the item is normally worn on the part of the body of the wearer and in which the portion of the hook member between the plane perpendicular to the central plane of the second fastening member and the plane of the slot prevents the removal of the hook member from the pin thereby securing the item around the part of the body of the wearer.