A head-protecting airbag device includes: an airbag loaded in a vehicle as a completely folded body folded to be storable in the storage portion; and a regulation member, to be arranged near a bent portion in the completely folded body at a time of conveyance. The regulation member is formed of a belt-shaped body having flexibility, and capable of regulating a twist of the completely folded body at the bent portion when the completely folded body is assembled into the vehicle. In a state where a protrusion part is engaged with a periphery of an assembly hole, both front and rear sides of the protrusion part are wrapped together with the completely folded body by a wrapping material. A length dimension of a portion between the assembly holes is set to be a length dimension which disenables one turn of twist in a circumferential direction of the completely folded body.