A substantially vertically extending concave portion is provided at a middle part of an impact absorbing face of an airbag body that deploys under a windshield so as to face a front seat occupant. With this configuration, an occupant who is seated in a regular seating position and wearing a seatbelt can be properly protected by preventing the neck area or the like of the occupant from being damaged. In addition, a bulging portion configured to bulge under the windshield and at an upper part of the concave portion is provided to the airbag body. With this configuration, it is possible to properly prevent the head area of an occupant who is not wearing a seatbelt from being damaged directly by the windshield.