An air bag which is light and pliable to be compactly housed and excellent in durability against a load applied thereto, upon the actuation of air bag, and long term aging, which is formed of two woven fabrics interwoven with each other to be a bag-shaped body, each composed of polyamide type synthetic fiber yarns containing copper compounds in a range from 30 to 200 ppm estimated in term of copper or cut pieces of the fabric sewn together to be a three-dimensional shape, the fabric having a product of a total fineness of warp or weft multiplied by a weave density of 16000 decitex·ends/2.54 cm or less, a load at 15% elongation in a range from 3 to 35 N/%/2.54 cm and a tensile work at break in a range from 7000 to 30000 N·%/2.54 cm.This air bag may be applicable to a driver's seat, a passenger's seat, and to side impact protection in a vehicle.