Side airbag for automobile and method of folding the same

There is provided a side airbag for an automobile having airbag modules (100,200,300), which selectively includes reinforcing pads (160), an inner cushion pad (150), a tube-type tether and a tear seam (136), all of which are piled in multi-layers, so that the side airbag may be developed with regulating the gas pressure duration without excentricity, in a useful and effective manner to successfully protect a driver and passengers seated in the vehicle. The cushion pads used in the side airbag require a small amount of materials, are easily seamed and easily folded, so as to reduce costs.