A curtain airbag device may include: an inflator configured to generate operating gas; a bracket part installed in a shape to abut on a side surface of the inflator, and having one side installed so as to be inclined in a direction away from the inflator; a cushion part inserted into a mounting space formed between the inflator and the bracket part, and inflated by the operating gas generated through the inflator; and a clamping part installed in a shape to surround outsides of the cushion part and the bracket part.