To provide a leash-fixing tool for a pet animal, so designed as not to engage a ring such as of a collar on an operative part to prevent the animal from escaping carelessly, resulting in a leash-fixing tool body's opening being developed unintendedly and the ring comes off.

The leash-fixing tool for an animal comprises a leash-fixing tool body 2 with a hook 22 integrated with the base 21, an operating member 3 threaded slidably through the base 21 of the leash-fixing tool body 2 by integrally providing an operating portion 33 via a connective part 32 on a pin part 31, and a spring provided on the base 21 of the leash-fixing tool body 2 and impelling the operative member 3 in the direction of closing an opening 2a formed in between the base 21 and the hook 22's tip. In this tool, the distance from the top edge face of the base 21 to the bottom-edge face of the operating portion 33 is set relative to the inside diameter of a ring so that the ring, engaged to a corner by the base 21 and the operating portion 33, comes into contact with the base 21 by passing through the operative part 33, when the operating portion 33 abuts against the hook 22 and effects closing of the opening 2a.