A ceramic dielectric composition is provided including 30 to 94% by mol of SrTiO.sub.3, 1 to 22% by mol of Bi.sub.2 O.sub.3 and 5 to 69% by mol of TiO.sub.2, and further including 0.1 to 20% by weight of MgO with respect to the total weight of the above-mentioned three compounds SrTiO.sub.3, Bi.sub.2 O.sub.3 and TiO.sub.2, whereby the ceramic dielectric composition has a high dielectric constant and a low dielectric loss and further the variations of the dielectric constant and the dielectric loss with respect to the variation of an applied voltage, are respectively, very small.