Alumina/zirconia ceramics containing Al.sub.2O.sub.3 in an amount of not less than 65 mass % and ZrO.sub.2 in an amount of 4 to 34 mass %, and further containing TiO.sub.2, MgO and SiO.sub.2. The ceramics effectively suppresses the growth of shape isotropic particles of alumina, suppresses the growth of zirconia particles, and has a high strength and a high hardness. Besides, the ceramics containing SrO features a high fracture toughness.