A curtain airbag device that can be applied to a small-width pillar. The curtain airbag device is accommodated in a region extending from at least an A-pillar to an upper portion of a window frame, and includes an airbag that is deployed in a curtain form near a side window of a vehicle interior in order to protect an occupant; and a gas generator that supplies inflation gas to the airbag. The accommodated airbag is formed in a rod shape by being folded in a roll form. When the airbag is accommodated, the airbag is partially compressed toward the center of the airbag at a narrow portion where an installation area of the A-pillar is narrow, in order to partially decrease a diameter of the airbag.