A signal processing device controls a plurality of signal processing units that process an input signal inputted via a signal line with wide bandwidth, via a control line with narrow bandwidth or the signal line, and includes: a storing unit configured to store correspondence information that associates instruction information indicating an instruction of control with respect to each of the signal processing units, with control information related to all of the plurality of signal processing units, among pieces of control information necessary for each of the signal processing units to execute content of control; and a transmitting unit configured to transmit the control information associated with the instruction information by the correspondence information, to the plurality of signal processing units via the signal line, when control is instructed with respect to the plurality of signal processing units.