A dielectric porcelain composition includes lead magnesium tungstate (Pb(Mg.sub.1/2 W.sub.1/2)O.sub.3), lead titanate (PbTiO.sub.3) and lead zirconate (PbZrO.sub.3) as main components at composition ratios of x, y and z respectively, wherein a point (x, y, z) in a ternary system is positioned on or within a boundary which comprises four straight line segments defined by four points of (0.725, 0.25, 0.025), (0.45, 0.525, 0.025), (0.30, 0.30, 0.40) and (0.475, 0.125, 0.40) in said ternary system as illustrated in FIG. 1, and wherein said main components are added with at least one rare earth oxide at a molar ratio in the range of 0.1-5.0 mol %.