OCCUPANT PROTECTION DEVICE

An occupant protection device that contributes to improving the restraint performance of a waist part of an occupant is disclosed. The occupant protection device 30, which is provided inside or below a seat cushion 2 of a vehicle seat 100, includes an airbag cushion 32 that can be expanded to push up a seat surface 26 of the seat cushion 2, and at least one inflator 34 (inflators 34a and 34b) that is activated in the event of a vehicle emergency. The at least one inflator 34 is configured to be activated at least once in the event of a vehicle emergency to supply expansion gas to an internal space of the airbag cushion 32, and the timing of supplying the expansion gas is controlled by varying the timing of gas generation from at least one gas generating part based on sensing from the vehicle.