The invention provides a dielectric composition based on a BaO-MgO-Nb2O5 system material (BMN system material) having a dielectric constant epsilon f of about 30, a large Q-value as a no-load quality coefficient and a comparatively small absolute value of the temperature coefficient tau f of its resonance frequency but containing no expensive Ta. The dielectric material has a composite perovskite crystal structure as the main crystal phase, wherein a predetermined amount of KNbO3 is added to a BMN system material. High frequency characteristics can be further improved by partially replacing Nb with Sb and partially replacing the B site of the perovskite crystal structure with Sn.
