The head-protecting airbag according to the present invention is formed by hollow-weaving method, and includes a gas admissive portion inflatable with inflation gas to separate its vehicle's inner wall and vehicle's outer wall, and a non-admissive portion admitting no inflation gas. The non-admissive portion includes mounting portions arranged in the upper edge of the airbag, and a marginal portion located around the gas admissive portion. The non-admissive portion partially has a two-ply structure where the hollow-woven cloth material separates into vehicle's inner cloth part and outer cloth part from the marginal portion having a one-ply structure. At least one of the mounting portions is formed by folding back a region of the two-ply cloth part to have a four-ply structure. The head-protecting airbag of the present invention remains stably attached to the vehicle body without breakage of the mounting portions even when a strong tension force rapidly and directly acts on mounting-hole peripheries of the mounting portions upon airbag deployment.