Domain walls play a central role in a subject of recent interest, the braneworld scenario. In particular, BPS domain walls are investigated in detail in D = 4, N = 1 SUSY theories. We should consider hypermultiplets to realize D = 4, N = 1 SUSY theory on the world-volume. In order to have a potential with discrete degenerate vacua, they must have gauge interaction, or nonlinearity of kinetic te...