Silicon boride (SiB6) was reported that have the characteristics of oxidization resistance and excellent hardness in the high temperature. On the other hand, Boron carbide (B4C) was known that have high hardness after the diamond, and high See-beck coefficient. It is able to expect that the SiB6-B4C composite ceramics have the characteristics of hardness, resistance oxidization, and high See-beck coefficient in the high temperature. SiB6-B4C ceramics were prepared by hot-press sintering method. The sintered body's chemical components were determined by using X-ray diffraction analysis and their relative density and electrical conductivity were measured.