To obtain a circular-weaving ground fabric for an air bag, which is rapidly developed, has an extremely slight air leakage, causes no warp fluffs due to low tension load applied to warps in weaving, has an extremely slight occurrence of wrinkles at a border between a double-weaving part and a single weaving part during coating processing and excellent qualities of woven fabric and a curtain-like air bag.

In the circular-weaving ground fabric for an air bag, having a developable and swellable double-weaving part and a connection belt formed on its outer periphery, the connection belt has single weaving parts that are arranged in parallel across a double-weaving part and comprise a basket weave texture satisfying formula 1,000≤K×N×W2/D≤3,000 [W is a fiber fineness (dtex); D is weaving density (yarns/2.5 cm); N is the number of yarns of the single weaving part; K is a coefficient represented by formula 1/√p (p is p/p basket weave texture)].