A control apparatus includes a semiconductor switch that is arranged between a DC power supply and a load to control a turning ON/OFF operation of the load, a counter electromotive force judging unit that determines whether a counter electromotive force produced on a first wiring line is greater than a threshold voltage, the first wiring line connecting the semiconductor switch to the DC power supply, and a control unit that controls the semiconductor switch so as to be turned OFF when the counter electromotive force judging unit determines that the counter electromotive force is greater than the threshold voltage.