A ceramic composition according to an embodiment of the present invention contains: a main phase component represented by CaMgSi2O6 or Ba4(Re(1-x), Bix)9.33Ti18O54; and an additive component containing a Li component and a B component, An observation field, a part of a sectional surface of the ceramic composition, is divided into a plurality of unit observation regions. Among all the unit observation regions, those containing no or little sintering agent component are referred to as the main crystal regions. An area percentage of main crystal regions relative to the observation field is 30% or more, the main crystal regions being the unit observation regions containing 0.5% or less by area of the additive component.