A curtain airbag device with which the position of a tether that pulls an end chamber during inflation and deployment thereof can be stabilized, thereby stabilizing the deployment behavior of the end chamber. A curtain airbag device 100 is housed in a side face upper portion of a vehicle cabin and inflated and deployed along the side face, and includes a main chamber 132 that is inflated and deployed using gas from an inflator 122, an end chamber 134 that is disposed on a front end 136 of the main chamber and inflated and deployed by gas received from the main chamber, a tab 144 attached to an upper portion of the main chamber, a bracket 128 fixed to the side face upper portion of the vehicle cabin, the tab being passed through the bracket, and a tether 126 attached so as to extend from a front end 138 of an upper portion of the end chamber to the bracket, wherein a length La of the tether is shorter than a distance Lb from the front end of the upper portion of the end chamber to the bracket in a case where the main chamber and the end chamber are inflated and deployed without the tether.