a center airbag cushion installed between left and right seats of a vehicle to protect a passenger from a shock generated by a side collision of the vehicle may include a first chamber part , a second chamber part comprising a left second chamber part and a right second chamber part respectively coupled to left and right sides of an upper end of the first chamber part to fluid - communicate therebetween , and a tension member provided on inner facing surfaces of the left and right second chamber parts , wherein the inner facing surfaces of the left and right second chamber parts face each other with a gap , and wherein the tension member has a rear end extending in a predetermined length rearwards and is fixed to a rear end of the first chamber part or the second chamber part therein .