The invention provides a dielectric filter including a metal case having an opening in the upper part, a metal lid of closing the opening, a dielectric resonance element placed on the internal bottom face of the case through a support, a bolt made of dielectric material inserted in a position in the lid corresponding to the dielectric resonance element, and a metal plate placed at the end of the bolt substantially in parallel with the upper face of the dielectric resonance element, wherein the position of the bolt is adjusted to change the space between the dielectric resonance element and the plate, whereby the resonance frequency is controlled.