Occupant protection system

In order to provide an occupant protection system that can easily be mounted to a seat, an occupant protection system (10) includes a seat pan (8) placed between the front parts of side frames (1a, 1b) of a seat; an airbag (12) arranged above the seat pan (8); and a gas generator (14) for inflating the airbag (12). The airbag (12) extends along the width direction of the seat pan (8), opposite ends of the airbag (12) being connected to the seat pan (8) through anchors (16). The gas generator (14) is arranged along the upper surface of the seat pan (8) and is fixed to the seat pan (8) with a bracket (14a). The gas generator (14) is connected to the airbag (12) through a pipe (18).