Airbag apparatus

An airbag apparatus for a vehicle, comprising

• a bag body which is expanded and deployed by expansion gas supplied when the vehicle receives an external impact,
• wherein the bag body includes:
• a base provided in a range from diagonally forward left to diagonally forward right of an occupant's head;
• a left section which is expanded and deployed so as to project rearward from a left edge of the base;
• a right section which is expanded and deployed so as to project rearward from a right edge of the base;
• and
• a coupling tether which is situated at a rear side of the base when the bag body is expanded and deployed, the coupling tether being configured to couple the left section to the right section,
• wherein the bag body is expanded and deployed to make the occupant's head in a pushing state when the vehicle diagonally receives an impact from front so that the occupant's head is displaced diagonally forward, a front surface of the occupant's head pushing a surface of the coupling tether and a side surface of the occupant's head pushing a surface of the left or right section,
• wherein a normal force and a dynamic friction force cause a first directional moment to turn the occupant's head in a first direction when the front surface of the occupant's head receives the normal force and the dynamic friction force from the surface of the coupling tether under the pushing state, and
• wherein a second directional moment acts to turn the occupant's head in a second direction opposite to the first direction, the second directional moment being caused by a normal force and a dynamic friction force which the side surface of the occupant's head receives from the surface of the left or right section.