SIDE AIRBAG AND CUT FORMATION THEREOF

PROBLEM TO BE SOLVED: To prevent generation of torsion or a pleat on the surface of an airbag in inflating a side airbag. SOLUTION: This side airbag, which makes an airbag formed out of a duct- shaped chamber inflatable, is provided with a fixed side surface 11 formed to fix the airbag to a vehicle along a curved fixing part which curves along the roof longitudinal member of the vehicle and a free side surface 15 which is unfolded by the inflation of the airbag fixed to the fixing part, bent along the main unfolding direction which is faced roughly vertically downward, positioned on the approx. opposite side to the fixed side surface 11 of the airbag in inflating, and forms the lower end side of the airbag. The cut of the airbag along the fixed side surface 11 has a roughly linear contour and a length roughly equal to the entire length of the fixing part, and the cut along the free side surface 15 has a roughly curved contour.