To not only obtain an original locking function but also miniaturize and lighten a sign lock, and to enrich fashion properties.

This sign lock is composed of a ring-shaped rod body 1, which has a shape bent in a ring form and in which one end 1a and the other end 1b are faced oppositely at a regular interval, a rotatable shaft 2, which is formed in a member interposed between one end 1a and the other end 1b of the ring-shaped rod body 1 and in which the base end 2b side is pivoted on the other end 1b side of the ring-shaped rod body 1 while the free end 2a side has length reaching one end 1a side of the ring-shaped rod body 1, and a sign lock body 3 externally fitted to the shaft 2 slidably.