The Microwave Flow Monitor is a solid flow sensor with the microwave technology. It can monitor the relative balance of flow rates in multiple bran chpipes divided from a main pipe and since the total flow rate of branch pipes and the one of a main pipe are monitored, it is possible to check the balance of flow rate and control the flow rate. Also it can be applied to various solids and since there is no protrusion inside pipe, no clogging will occur. Further it can be used for the various applications such as a combustion boiler, a blending bin and a distribution system.