To provide a buckle for a human body protective clothing, which is excellent in safety.

The buckle is attached to a reinforcing belt B around a trunk which is utilized for fastening a body part of the human body protective clothing for vehicles, and composed of one connecting clasp 6 and a pair of hooking clasps 5, each of which is attached to the reinforcing belt around the trunk and is hookingly engaged with the connecting clasp 6. The connecting clasp 6 is formed with a pair of cut off openings 66, 67 which are divided by a middle supporting portion 65, and likewise, each hooking clasp is formed with a pair of cut off openings 56, 57 divided by a middle supporting portion 55. A width of the hooking clasp is larger than a diagonal length of the cut off opening in the connecting clasp so that the hooking clasp can not slip off even when the hooking clasp is matched to the diagonal of the cut off opening, which has a size the hooking clasp can pass through the cut off opening in a condition the hooking clasp is raised sideways.