a dielectric filter includes two dielectric resonators each having a dielectric base body including first , second , third and fourth side surfaces and first and second end surfaces . a through hole is provided from the first end surface to the second end surface to define an inner surface . an outer conductor is located on and partially covers the four side surfaces . uncovered portions of the second and third side surfaces are provided that are adjacent to each other and bounded by the outer conductor in three directions . an uncovered portion of the fourth side surface is adjacent to an uncovered portion of the first side surface and the first end surface , and is separated from the third side surface by the outer conductor . an inner conductor is located on the inner surface . a connection conductor is also located on the second end surface and connects the inner conductor to the outer conductor . an interstage coupling electrode is located on the uncovered portion of the first side surface . an area of the uncovered portion of the first side surface extends in at least three directions from the interstage coupling electrode and separates the interstage coupling electrode from the outer conductor . an input / output coupling electrode is located on the uncovered portion of the second and third side surfaces . areas of the uncovered portions of the second and third side surfaces extend in three directions from the input / output coupling electrode and separate the input / output coupling electrode from the outer conductor . the the outer conductor of a first dielectric resonator is electrically connected to the outer conductor of a second dielectric resonator .