The purpose of the present invention is to provide a clasp for use with animals with which the work of clasping and unclasping is easy and which is capable of limiting the probability that the operation part will be unclasped accidentally due to twisting or to other causes. The purpose is achieved by means of a clasp (200) provided with: a main body (4) having a forked section (3) formed in the leading end (10) side extending from a base section (2) where a base ring (1) is connected and an open-close mechanism (7) for opening and closing the open section (5) of the forked section (3) and for clasping and unclasping, in cooperation with the forked section, an object (6). The open-close mechanism (7) comprises: an open-close member (8) that advances and retracts in the open section (5) between one side (3a) and the other side (3b) to open and close the open section a spring (9) impelling the open-close member (8) so as to close and an operation part (21) that protrudes from the surface (4a) where the prongs of the forked section (3) of the main body lie are aligned. The operation part (21) moves from the other side (3b) to the one side (3a) in the direction that the prongs of the forked section (3) are aligned in response to the closing operation in which the open-close member (8) advances from the one side (3a) to the other side (3b) of the forked section (3), and when the operation part (21) is operated by being moved from the one side (3a) to the other side (3b), the open-close member (8) is retracted against the opposing force of the spring (9) and is opened.La présente invention vise à créer un fermoir destiné à être utilisé avec des animaux, avec lequel le travail de serrage et de desserrage est facile, et qui est apte à limiter la probabilité en ce que la partie actionnement sera desserrée accidentellement en raison dune torsion ou dautres causes. Linvention est obtenue au moyen dun fermoir (200), qui comprend : un corps principal (4) ayant une section fourchu
