A dielectric ceramic composition comprising forsterite in an amount of 93.0 to 99.0 mol % when calculating in terms of 2MgO.SiO2 and calcium titanate in an amount of 1.0 to 7.0 mol % when calculating in terms of CaTiO3 as main components, and as a subcomponent, aluminum oxide in an amount of 0.2 to 5 mass % when calculating in terms of Al2O3 per 100 mass % of said main components. According to the present invention, a dielectric ceramic composition, capable of having both low permittivity and good frequency-temperature characteristic as well as ensuring high Qf value and further having sufficient mechanical strength, and suitable to use in an antenna, a filter and the like used in the high-frequency region, can be provided. Also, the present invention allows providing a dielectric ceramic composition further having resistance to reduction in addition to all of the above properties.