An air bag device for pedestrian includes an inflator which discharges an inflating gas, in operation, and an air bag which is inflated with the inflating gas supplied from the inflator thereby to cover a front face of the front pillar. The air bag is contained in a folded state, in an area covered with the front fender panel which is positioned in front of a front pillar and outside of a vehicle along a lateral direction of a hood panel. The front fender panel includes a cover part which is positioned at its back edge close to the front pillar, and arranged so as to cover an upper part of the air bag in the folded state. The cover part is deformed and opened, when it is pressed with the air bag which is being inflated, thereby to protrude the air bag so that the air bag can cover the front face side of the front pillar.