An objective is to inflate an inflation portion to an upward position, corresponding with a temple area of an occupant, at the time of a side impact. At a shoulder portion of a seatback 26 of a vehicle seat 12, there is an inflation-time cross-sectional shape regulation component 22, through which an occupant restraint webbing 16 passes. The occupant restraint webbing 16 has an inflation portion 18 that corresponds with a cephalic region 14H of an occupant 14 at the time of inflation. At the time of inflation of the inflation portion 18, the inflation-time cross-sectional shape regulation component 22 regulates such that a cross-sectional shape of the inflation portion 18 is an oblong shape which is long in a vertical direction. Therefore, an inflated shape of the inflation portion 18 is regulated by the inflation-time cross-sectional shape regulation component 22 at the time of the side impact, and the inflation portion 18 can be caused to inflate up to a position corresponding with a temple portion 14S of the occupant 14. Thus, inertial force in a vehicle lateral direction of the cephalic region 14H of the occupant 14 can be absorbed by the inflation portion 18.