In dividing units, signals propagating between input ports- and output ports and between input ports and output ports have phases shifted by 90° from phases of signals propagating between the input ports and the output port and between the input ports and the output ports. Amplifiers output amplified signals that are in phase to the dividing units. A combining and dividing unit outputs a combined signal obtained by combining signals from the output ports of the dividing units to an input port of a combining unit. A combining and dividing unit outputs a combined signal obtained by combining signals from the output ports of the dividing units to an input port of a combining unit.