A curtain airbag apparatus may include: a cushion part disposed at the top of a pillar part; one or more guide members connected to the cushion part and configured to fix the cushion part to a vehicle body; and a cushion moving part connected to the cushion part, disposed between the guide members and the vehicle body, fixed to the guide members, and configured to deform the guide members to move the cushion part to an indoor side of the vehicle body, while inflated by gas injected from an inflator.