A balance-type mixer is provided which is capable of increasing the ease of mounting of a circuit board (4) into a dielectric line apparatus, capable of easily achieving matching between a dielectric line and diodes (81, 82), and capable of reducing conversion loss. A first conductor pattern (51) is disposed in a direction nearly vertical to first dielectric strips (31a, 31b) which constitute a first NRD guide, first and second filter circuits (6, 7) are provided at positions at which the dielectric strips (31a, 31b) are sandwiched, thus forming a first resonance circuit, and beam lead diodes (81, 82) are mounted in series within the resonance circuit. Further, a second conductor pattern (52) is extended from the nearly central position of the filter circuits (6, 7), and a third filter circuit (9) is provided, thus forming a second resonance circuit. A second NRD guide based on second dielectric strips (32a, 32b) is connected to the second resonance circuit.