The present invention relates to a dielectric device that is suitable for miniaturization and height reduction and is surface-mountable. In a resonator unit Q1, a first hole 41 is provided to a dielectric substarate 1, extends from a surface 21 toward a surface 22 opposite thereto, opens in the surface 21, and has a first internal conductor 61 in the interior. A second hole 51 is provided to the dielectric substarate 1, opens in a surface 23 adjacent to the surface 21, extends from the surface 23 toward a surface 24 opposite thereto, and is connected with the first hole 41 in the interior of the dielectric substarate 1. The second hole 51 has a second internal conductor 81 in the interior, and the second internal conductor 81 is connected to the first internal conductor 61 in the interior of the dielectric substarate 1.