A dielectric ceramic composition which consists essentially of bismuth oxide, calcium oxide and niobium oxide, wherein when the dielectric ceramic composition is expressed by a formula xBiO.sub.3/2 -yCaO-zNbO.sub.5/2 and the x, y and z are plotted in a ternary system diagram so as to total 1.0, the x, y and z fall in a region enclosed by a pentagon having the following vertexes A, B, C, D and E,A: (x, y, z)=(0.55, 0.16, 0.29)B: (x, y, z)=(0.5, 0.21, 0.29)C: (x, y, z)=(0.44, 0.24, 0.32)D: (x, y, z)=(0.44, 0.2, 0.36) andE: (x, y, z)=(0.5, 0.175, 0.325); anda multilayer microwave device including a dielectric layer formed by the dielectric ceramic composition.