To provide an occupant restraint system for allowing the gas from a gas generating unit to blow into a bag even in the case of using a gas generating unit for injecting gas in a non-axial direction of a duct.

The bag 12 arranged under a seat cushion is connected to the gas generating unit 14 through a duct 16. The duct 16 is fitted on a nozzle part 26 of the gas generating unit 14, and the inner peripheral surface of the duct 16 faces to a gas injection opening 30 provided in a side peripheral surface of the nozzle part 16. When the gas generating unit 14 is operated to inject gas, gas from the gas generating unit 14 is injected in the radiating direction of the nozzle part 26 from each of the gas injection openings 30, and thereafter, the gas collides with the inner peripheral surface of the duct 16, and flows, while changing flow direction thereof to the axial direction of the duct 16.