AIRBAG FOR SIDE COLLISION

Provided is a side airbag for side collision which is deployed between two seats in a width direction of a vehicle to prevent occupants siting on the two seats from colliding with each other. The airbag includes a chest protective area to protect a chest of an occupant; a head protective area extending upward from the chest protective area to protect a head of the occupant; and a support area extending rearward from the head protective area and making contact with a head rest, which is provided on an upper portion of a back of the seat, so as to be supported by the head rest, wherein, the support area of the airbag is supported by the head rest when the vehicle collision occurs to prevent a head of an occupant who sits near a crashed side from moving rearward of the head protective area, thereby preventing the head of the occupant sitting near the crashed side from colliding with a head of a counterparty occupant who faces the occupant sitting near the crashed side in the width direction of the vehicle.