A dielectric filter includes a dielectric block having substantially a rectangular parallelepiped shape, a plurality of internal-conductor-formed holes provided substantially parallel to one another in the dielectric block, each including an internal conductor formed on the internal surface thereof, an external conductor formed on the external surface of the dielectric block, and an input/output electrode formed on the external surface of the dielectric block. In the dielectric filter, the input/output electrode is formed from a side face, which is an end face of the dielectric block in a parallel direction of the internal-conductor-formed holes, to a bottom face, which is a mounting face of the dielectric block facing a mounting substrate, a capacitance is generated between the internal conductor of a first internal-conductor-formed hole closest to the end face and the internal conductor of a second internal-conductor-formed hole in the neighborhood of the first internal-conductor-formed hole, and the cross section of at least the first internal-conductor-formed hole is a noncircular shape extending in a direction parallel to the side face.