an airbag module fixed to a seat frame of the vehicle seat;

a first webbing and a second webbing surrounding the airbag module together with the seat frame and guiding an inflating airbag to an airbag outlet on a seat surface;

a locked portion provided on a first end part on a side opposite to a side of the airbag outlet of the first webbing;

a fixed portion provided on a second end part on a side opposite to the airbag outlet side of the second webbing; and

a locking member formed of a member having rigidity and having a fixing portion to which the fixed portion of the second webbing is fixed and a locking portion for hooking and locking the locked portion of the first webbing,

wherein the locking portion is formed having a hook shape by a slit portion having such a shape that the locked portion of the first webbing can be inserted, and

a retaining portion which suppresses removal of the locked portion inserted into the slit portion from the slit portion is formed on the locking portion, or the locked portion of the first webbing is configured such that the first end part of the first webbing is folded back and sewn into a loop shape.