A curtain airbag device capable of preventing a cushion from damaging a front pillar trim or being caught by the front pillar trim upon deployed. A cushion 102 of a curtain airbag device 100 is inflated and deployed at a side wall of a vehicle interior to restrain an occupant. The curtain airbag device 100 includes: a cushion 102 having a bag shape and inflated and deployed on the vehicle front side of a passenger seat; and a first strap 148. The first strap 148 has one end 156 attached to a front pillar 104 and the other end 162 attached on the vehicle inner side of the cushion 102 in an elongate stored form. The first strap 148 moves to the vehicle inner side and is strained by inflation and deployment of the cushion 102 pushing out a front pillar trim 184 that covers the front pillar 104 to the vehicle inner side.