Passenger seat airbag

1. A passenger seat airbag, which is folded and accommodated in an accommodation portion provided in an instrument panel located in front of an occupant seated in a passenger seat, makes inflation gas flow inside, and expands and inflates toward a rear side of a vehicle while inflating, the passenger seat airbag comprising:

a bag main body composed of a flexible sheet body, the bag main body including:

an occupant side wall portion arranged on an occupant side portion when the inflation is completed; and

a peripheral wall portion extending from a peripheral edge of the occupant side wall portion and converging toward a front end side attached to an accommodation portion side; and

a left-right tether, arranged in the bag main body to connect a left wall portion and a right wall portion facing each other on a left-right direction side of the peripheral wall portion, the left-right tether preventing left and right outward protrusions of a connecting portion with the left wall portion or the right wall portion, wherein:

the connecting portion of the left-right tether is composed of a tether main body of a strip-shaped sheet body having a flexibility and includes a pair of strip portions and an intermediate portion which is sewn and connected to the left wall portion or the right wall portion at an area between the strip portions;

the left-right tether is formed of terminals of the strip portions sewn together at once as four sheets stacked together; and

a sewn portion for sewing the intermediate portion to the left wall portion or the right wall portion is configured as a substantially rectangular shape having a pair of strip-side sides on a strip portion side and a pair of non-strip-side sides connecting both ends of the pair of strip-side sides.

2. The passenger seat airbag according to claim 1 , wherein:

the tether main body is arranged on a left wall portion side and a right wall portion side; and

the left-right tether is configured by connecting terminals of the pair of strip portions extending from each of the connecting portions.

3. The passenger seat airbag according to claim 2 , wherein:

in the bag main body, a front-rear tether which connects a front end side at the time of completion of inflation and the occupant side wall portion substantially along a front-rear direction is arranged above or below the left-right tether; and

the tether main body is arranged such that, when the inflation of the bag main body is completed, one of the strip portions on a side of the tether main body which is closer to the front-rear tether is aligned with a width direction substantially along the front-rear direction so as to approach an edge of the front-rear tether on an up-down direction side on a side of the front-rear tether which is closer to the left-right tether.