A pedestrian airbag apparatus in which smooth inflation and deployment of an airbag are achieved without using an inflator having a high output is provided. An opening 3a for allowing passage of the airbag provided on a bonnet hood 3 is covered by a lid 20. A rear edge 20r of the lid 20 is rotatably joined to the rear edge side of the opening 3a via hinges 21, and a front edge 20f and the rear edge 20r of the lid 20 are disengageably engaged with a peripheral edge portion of the opening 3a by clips 30, respectively. The clips 30 on the front edge 20f side and the hinges 21 on the rear edge 20r side are arranged so as to be shifted in the vehicle width direction. The clips 30 on the front edge 20f side and the clips 30 on the rear edge 20r side are arranged so as to be shifted in the vehicle width direction.