To provide a saddle antitheft connector formed by fixing both ends of a wire stretched between a saddle and a frame of a bicycle.

This antitheft tool is formed of a connector provided with a latch receiver part, in which a latch part formed in an end of the wire is fitted to latch, and a wire lock piece for fixing the latched latch part to the connector, The wire lock piece has a lock piece provided with an insertion hole for insertion of a tip of the latch part of the wire, and the lock piece rides over the latch part, while deflecting at a tip thereof in a direction for separating from the latch part of the wire latched in the latch receiver part, and the lock piece is reset by the rebound energizing force to fit the latch part in the insertion hole for connection.