An airbag device capable of restraining an obliquely forward movement of an occupant. The airbag device includes: an inflator which is operated by a signal from a sensor that detects a collision and which discharges expansion gas; to deploy and expand the airbags. The airbags include: a first airbag which deploys to the front of an occupant for restraining a forward movement of the occupant; and a second airbag which is joined to a side part of the first airbag on a cabin center side and restrains an obliquely forward movement of the occupant. The collision sensor is capable of discriminating between a first collision mode which is not accompanied by rotation of the vehicle and a second collision mode which is accompanied by a rotation of the vehicle in a horizontal plane, and the second airbag is deployed only when the second collision mode occurs.