To provide a multi-port amplifying device easy to realize optimum design by eliminating a deflection of gain and phase among families of input-side hybrid network, and capable of making the input-side hybrid network small and low cost greatly and further improving the installation of the device by making the body smaller.

In the multi-port amplifying device, an individual hybrid constituting an input-side hybrid network is realized by using a digital quadrature base band 90° hybrid circuit so that a deflection of gain and a deflection of phase among families of input-side hybrid network can be eliminated. Then, a necessary value of gain deflection and phase deflection among the families required for the device synthesis can be distributed only to the amplifier and an output-side RF band hybrid network, and the optimum design is realized easily. In addition, a process is carried out by the digital quadrature base band signal system, so the input-side hybrid network can be made small greatly and realized at low cost.