To provide a jaw belt apparatus of a helmet capable of simply attaching a first hook of a belt end-fixing means to the jaw belt.

The first hook 15 is composed of a hook body 15 each integrally forming engaging parts 22 and 22' on one side of a mounting flange 21 and a connector 23 having a nearly T-shaped cross section passing through an attaching hole 31 of the jaw belt 5, and a connecting member 17 forming a fitting groove capable of fitting into a vertical wall 23a for the connector 23 and a housing 28 capable of fitting into a horizontal wall 23b of the connector 23 in or on a holding flange 27 capable of holding the jaw belt 5 in corporation with the mounting flange 21.