We have calculated the static yield stress of electrorheological fluid directly introducing cubic particle chains arranged in a triangular lattice to elucidate the influence of the many‐body effect. The shape of the stress‐strain curve at a high concentration of particles is much different from that at a low concentration, and the static yield stress saturates at a high concentration (&fgr;=0.4), the same as is the case of spherical particle chains arranged in a rectangular lattice. In both cases of low and high volume fractions, the yield stress increases in proportion to the permittivity ratio of particles and dispersion fluid.