PURPOSE: To provide a ceramic having low dielectric loss and good temperature stability by constituting the high-frequency dielectric ceramic with specific constituents.

CONSTITUTION: Fine grains of BaBi2Ta2O9 and/or BaBi2Nb2O9 and Cr2O3 are contained in BaNd2Ti5O14 having a high dielectric constant in the formula I, where (x) is set to 10-25%, and Cr2O3 fine grains serving as an additive is set to 0.5-2.5wt.% against the whole ceramic. These powder is normally synthesized by the solid phase reaction method, the calcining temperature is preferably set to 1,200-1,330°C when the powder of BaNd2Ti5O14 is synthesized, and the powder having higher purity, a single phase, and good degree of sintering is obtained. The powder is pulverized until the grain size of the mixed powder becomes the sub-micron order, i.e., 1μm or below, then the sintering temperature is set to 1,000-1,200°C to suppress the evaporation of Bi and make a composite material dense.