Provided is a combiner comprising a cavity and a cover plate covering the cavity. A plurality of signal input ports and a combined signal output port (100) are arranged at a side wall of the cavity. A plurality of signal cavities are formed in the cavity. Each signal cavity connects the combined signal output port (100) to a corresponding signal input port. The present invention is characterized in that the plurality of signal cavities are arranged around the combined signal output port (100) serving as the center of a circle within a central angle greater than 90 degrees and less than 360 degrees. The present invention realizes input, resonant coupling transmission, combination and output of multi-channel signals. The combiner has a reasonably arranged and compact internal structure, and is highly reliable.