A passenger seat airbag includes: a bag main body; and a left-right tether, arranged in the bag main body to connect a left wall portion and a tight wall portion facing each other on a left-right direction side of the peripheral wall portion, preventing left and right outward protrusions of a connecting portion with the left wall portion or the right wall portion. The connecting portion 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 between the strip portions. 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 the strip portion side and a pair of non-strip-side sides connecting both ends of the pair of strip-side sides.