An occupant protecting device provided inside or below a seat cushion of a vehicle seat, containing: an airbag cushion capable of expanding and deploying to push up a seat surface of the seat cushion; and an inflator that supplies gas for expansion and deployment into the airbag cushion in the event of a vehicle emergency. The airbag cushion has front attaching points and rear attaching points attached to the vehicle seat side, and an expanding and deploying part that is expanded and deployed by the gas from the inflator. At least a portion of the expanding and deploying part overlaps itself in an up-down direction by folding between front attaching points and rear attaching points in a condition prior to expanding and deploying.