An apparatus for fixing a curtain air bag cushion to a pillar of a vehicle includes a cushion bracket configured to be attached to the pillar. The cushion bracket has a fixing portion provided with a bolt hole, a support portion provided with a cover hole, and locking grooves between the fixing portion and the support portion. A cushion tab cover is configured to pass through the cover hole. A cushion band has a cover end coupled to the cushion tab cover and a hole end provided with a band hole. The band hole is configured to receive the first side of the cushion bracket such that the hole end of the cushion band is seated in the locking grooves.