A hood airbag device that includes an inflator, and an airbag. The inflator is provided inside a hood at a position corresponding to an opening formed in the hood. The inflator is disposed such that a gas-injection port (is positioned closer to the rear edge of the opening than to the front edge of the opening in the vehicle fore-and-aft direction. The airbag, which is provided inside the hood, passes through the opening and is deployed toward the outside of a vehicle body, due to the pressure of gas supplied from the inflator. Accordingly, the reference position for deployment of the airbag can be made closer to the rear of the vehicle in the vehicle fore-and-aft direction. Thus, the airbag can be deployed to a large extent in the area closer to the rear of the vehicle in the vehicle fore-and-aft direction.