PURPOSE: To remarkably suppress the coupling of adjacent filters excellent in packaging efficiency.

CONSTITUTION: Filters 31, 32, 33 and 34 using a microwave band and a quasi- millimeter wave band as their passing bands are folded at a face in parallel with an electric field and two filters are constituted as a set placed adjacent to each other while a conductor is shared between them and four filters of two sets are arranged in axialy symmetry to an input and output common rod 10. The filters 31, 32 form input section filters and the filters 33, 34 form output section filters, an input signal from each input section filter is outputted from the input output common rod 10 as a synthesis signal and the signal inputted from the input and output common rod 10 is outputted from the filters 33, 34 with branching. Common rods 15, 18, 21 and 24 are a part of the resonance rod forming respective filters.