Curtain air bag for vehicles

A curtain air bag formed so that an auxiliary inflatable chamber adapted to reduce to as great an extent as possible a substantial decrease in a protective region of an air bag body can be formed. The air bag body is deployed into the interior of an automobile by introducing a high-pressure gas, which is ejected from an inflator at the time of the occurrence of collision of the automobile with something, into the interior of the air bag body. An auxiliary inflatable chamber defined with respect to a main inflatable chamber is obtained by sewing the air bag body by a substantially one sewing line using a multi-thread chain stitch method or the like. The auxiliary and main inflatable chambers are communicated with each other via a narrow orifice type gas flow restriction passage