A digital mixing system is provided in which a console section and an engine section that executes signal processing can operate consistently in accordance with control signals input to the console section and the engine section. The digital mixing system has a plurality of input signal systems and a plurality of output signal systems. Input signals from the input signal systems are subjected to a mixing process and the mixed signals are output to the output signal systems. In a console section, panel operating elements are used to input parameters relating to the mixing process, and a first control device generates a mixing control signal in response to operation of the panel operating elements or to a first control signal input via a first input terminal or a first communication interface, and outputs the mixing control signal to the first communication interface. In an engine section, a mixing processing device executes the above mixing process, and a second control device controls the mixing process executed by the mixing processing device in response to the mixing control signal input via a second communication interface and outputs a second control signal input via a second input terminal to the second communication interface. Communication lines connect between the first communication interface and the second communication interface.