A curtain airbag apparatus may include: an inflator part configured to inject gas; a main cushion part expanded by the gas injected from the inflator part, and coupled to a car body; and a cushion moving part interposed between the main cushion part and the car body, and expanded by the gas injected from the inflator part so as to move the main cushion part. The gas transferred to the cushion moving part may be passed through the cushion moving part and transferred to the main cushion part.