A substrate connecting structure includes a circuit substrate where an electrical component is installed on the back face, a signal cable into which a plurality of signal transmission lines electrically connected to first signal line connecting portions and to second signal line connecting portions, respectively, are inserted, and a coupling member that is formed by a conductive member including a fixing section disposed at the end portion of the signal cable, a flat section on the front face of the circuit substrate, and a through hole, the coupling member fixing the signal cable and the circuit substrate, wherein the central axis of the signal cable is displaced toward the back face side with respect to the central axis of the circuit substrate.
