Opposite end portions of an airbag made of a folded metal plate and formed into a tubular shape are capped by respective end caps and are attached to an attachment surface of a front pillar, and the airbag is deployed along the front pillar by use of gas produced by an inflator, thereby protecting by the airbag a pedestrian that collides with the front pillar. Bolts penetrating through long holes formed in the end portions of the airbag and bolt holes of the end caps are screwed to weld nuts, and thereby the end portions of the airbag are slidably supported by the end caps. Accordingly, when the airbag is deployed the long holes slide with respect to the respective bolts toward inside in a longitudinal direction of the airbag, and a tension in the longitudinal direction of the airbag is prevented from acting on a metal plate of the airbag, thereby enabling the airbag to be deployed reliably near the end caps. Therefore, it is possible to inflate the airbag evenly along its entire length and thereby enhancing the shock absorbing performance when a pedestrian collides.