The present paper investigates the ultimate compressive strength of a simply-supported wide panel reinforced longitudinally by multiple stiffeners. It was clarified in the previous paper that in the case of one stiffener, the ultimate behaviors depend upon the equivalent flexural rigidity γ _e of the stiffener and they are classified in the three modes by the specific values of γ _e : γ₁ and γ₂. The same tendencies are observied in the case of multiply stiffened panels ; weak stiffeners (γ _e < γ₁) can not prevent panels from overall deformation, while strong stiffeners (γ _e >γ₂) are effective to be panel breakers and only local deformations are dominent even at the ultimate strength. If γ₁<γ _e <γ₂, overall deformation interacts with local buckling mode. It is also shown that the ultimate strength largely depends upon the in-plane constraint conditions. The simple approximation formulas are proposed for estimation of the ultimate strength.