To provide an airbag for a front passenger seat, wherein a structure is simple, raw material and manufacturing costs are reduced, no excessive loads are applied on the base cloth of an airbag main body, a direct influence by high-temperature gas from an inflator is prevented, and an ideal expansion form is provided.

In airbag main body 13 made of a cloth bag having a gas introduction port forming a crust and connected to the gas generation port of an inflator 8, a gas guiding cylinder 14 sharing the gas introduction port and shorter in dimension than the main body 13 is housed therein. The gas guiding cylinder 14 directly guides gas generated from the inflator 8 to a required position in the airbag main body 13 separated from the gas introduction port, and discharges the gas from the position into the airbag main body 13.