Disclosed is an airbag apparatus for a vehicle. The disclosed airbag apparatus for a vehicle includes a main cushion part configured to support a passenger's body by being deployed, a vent hole part formed in the main cushion part and configured to pass gas, a tube part coupled to the main cushion part and configured to guide a movement of the gas passed through the vent hole part, and a sub-cushion part coupled to the main cushion part, formed to surround the tube part, and configured to support the head of the passenger at the time of deployment.