Airbag apparatus

An airbag apparatus comprising:

• an airbag having a first expansion chamber, and a second expansion chamber, wherein the airbag has a joint portion where an outer periphery of a base fabric sheet is joined;
• a communication port for connecting the first expansion chamber and the second expansion chamber to each other in the airbag, wherein the communication port has an edge;
• a gas supply port arranged inside the second expansion chamber and configured to discharge inflation gas toward an inside of the communication port, wherein the gas supply port supplies the inflation gas to an inside of the airbag;
• and
• a communication passage extending from the edge of the communication port, serving as a starting point, toward an inside of the first expansion chamber, and the communication passage having an inner wall. Wherein,
• at deployment and inflation of the airbag, the communication passage extends across a space between the joint portion of the airbag, and the gas supply port, and
• the inflation gas discharges from the as supply port and flows into the communication Passage;
• and when initially inflating and deploying, the inflation gas collides with the inner wall of the communication passage.