SIDE AIRBAG

The present invention provides a side airbag capable of fully absorbing impact directed to a chest region while keeping an arm from being pressed against the chest region due to inflation. A side airbag 30, an arm facing section 38 which faces an arm H2 of the occupant H in an inflated state has a dented shape and serves to push up the arm H2 to a position where the arm H2 does not overlap a chest H3 region of the occupant.