In a fault diagnosis system (10) in a load driving arrangement, the fault diagnosis system detecting a fault in the load driving arrangement in which a controller (13) outputs a control signal to a driver (12) and the driver (12) drives a load (11) according to the control signal, a fault detecting unit (21) and an exclusive OR circuit (22) are provided to enable outputting, as a monitor signal, a signal opposite to the control signal upon detecting a fault in the load driving arrangement and outputting, as a monitor signal, the same signal as the control signal when not detecting a fault, a monitor signal output from the exclusive OR circuit (22) is input to the controller (13), and the controller (13) compares the control signal and the monitor signal and diagnoses whether a fault occurs in the load driving arrangement, based on the result of the comparison.