The original design of the synchronously tunable combined four-channel ferrite filter is given. It is a functional unit consisting of four microwave systems of ferrite filters with coupling loops (one such microwave system in each channel) and a common magnetic system for these filters, which ensures their synchronous tuning in the frequency range of 2-4 GHz. The structural solution of the microwave system in the form of a module allows one to obtain both a bandpass ferrite filter and a band-reject ferrite filter. The results of experimental research are provided. They showed that such a four-channel controllable ferrite filter has not only improved design and technological indicators but also a high decoupling between channels. It can be successfully used not only in measuring equipment but also in modern multichannel microwave communication equipment and radar.