A dual TM-mode dielectric resonator apparatus comprises a dual TM-mode dielectric resonator consisting of two columnar TM-mode dielectric resonators (1) crossed inside a cavity (2); and a partition plate (3) providing a window for electromagnetic field coupling between an external apparatus and the dielectric resonator. The partition (3) is disposed on the side surface of the cavity (2) opposing the external apparatus and constituted by forming a first shield conductor (30a) on a first main plane (S1) of a dielectric sheet (50) and a second shield conductor (30b) on a second main plane (S2). The first shield conductor (30a) includes parallel slits (32) formed in parallel with the longitudinal direction of one of the TM mode dielectric resonators, while the second shield conductor (30b) includes slits (31) formed in a region substantially opposed to the first slits (32). Further, a plurality of such dual TM-mode dielectric resonator apparatus described above are combined to form a band-pass filter. Accordingly, the degree of electromagnetic field coupling can be adjusted easily and precisely by adjusting the width of the first slits (31).