A head-protecting airbag according to the present invention is normally
folded and housed in an upper edge of windows inside a vehicle, and
deployable downward from the upper edge of windows upon inflow of
inflation gas to cover the vehicle's inner side of the windows. The
airbag internally includes a tether joined to the vehicle's inner side
wall and the vehicle's outer side wall for regulating the clearance
between the inner side wall and the outer side wall as the airbag is
completely inflated. The tether is disposed along the front-rear
direction of the vehicle. A joint portion of the tether to the vehicle's
inner side wall is located at lower level than a joint portion of the
tether to the vehicle's outer side wall as viewed in a vertical section
taken along the vehicle's transverse direction. The head-protecting
airbag of the present invention is able to expand along the windows.