The $alpha$-alumina/fused alumina/$eta$"-alumina specimens were fabricated by addition of fused alumina to $alpha$-alumina/$eta$"-alumina system. The sintered densities with and without fused alumina were almost same. But, the bending strength was decreased due to the presense of defects caused by the inhomogeneous dispersion of large fused alumina particles. And the fracture toughness was also decreased because the crack propagated through the fused alumina particles due to the imperfection of $eta$"-alumina coating around them.