To prevent positional deviation in a folded back portion of a deployment restriction sheet reliably, an air bag device includes an air bag 1, an inflator 7 for deploying the air bag 1 by supplying the air bag with a generated gas, an air bag case 3 used to attach the inflator 7 and store the air bag 1, a retainer 6 for fixing an opening portion peripheral edge of the air bag 1 to the air bag case 3, and a deployment restriction sheet 11 that covers the air bag 1 from a vehicle body rear side to a vehicle body front side when the air bag 1 is stored. In the deployment restriction sheet 11, a folded back portion 11c is subjected to tacking 11d so as to separate upon application of a predetermined load A, and a rupturable portion 11e that ruptures upon application of a predetermined load B, which is larger than the load A, is provided on a first end 11a side positioned on the vehicle body front side. The first end 11a is attached to an air bag main body. A second end 11b is installed on the air bag main body. As a result, positional deviation of the folded back portion does not occur, and a cushioning effect can be applied to an occupant effectively.