A crystal constituting a dielectric porcelain, comprised of a first crystal group composed of crystal grains of 0.2 atomic % or less calcium concentration and a second crystal group composed of crystal grains of 0.4 atomic % or more calcium concentration, wherein the ratio of concentration of each of magnesium and a first rare earth element contained in a center portion to that contained in a surface layer portion of crystal grains constituting the first crystal group is greater than the corresponding concentration ratio of crystal grains constituting the second crystal group, and wherein on a polished surface resulting from polishing of the surface of the dielectric porcelain, when the area of crystal grains of the first crystal group is referred to as a and the area of crystal grains of the second crystal group referred to as b, the ratio of b/(a+b) is in the range of 0.5 to 0.8.