Occupant protecting device

In order to provide an occupant protecting device which makes it possible to inflate a bag of an inflatable seatbelt device or exerting a pre-tension upon a seatbelt by a gas generator for inflating a bag disposed at the front portion of a seat cushion, an occupant protecting device including an inflatable tube (20) disposed under the front portion of a cushion pad. Gas from an inflator (34) enters the tube (20) through a cylinder (30). A piston (40) is disposed inside the cylinder (30), and is connected to a lap anchor (44) through a wire (42). A structure which causes a bag (60) to be inflated by the gas from the inflator (34) may also be used.