Airbag and airbag apparatus

In order to ensure enough high inner pressure of an airbag at the initial stage of inflation even with a low-output inflator and to make gas flowing out from a vent hole of the airbag to disperse over a wide range, an airbag (1) is made by sewing together a front panel (2) and a rear panel (3). The rear panel (3) is provided with a vent hole (5). A nozzle (6) is disposed to extend from the periphery of the vent hole (5). The nozzle (6) is made of fabric into a cylindrical shape and is sewn to the rear panel (3). The nozzle (6) wags or moves during gas flows out through the nozzle (6), whereby the gas disperses over a wide range. The airbag (1) is folded in a state that the nozzle is arranged inside the airbag (1).