Abstract: In a DC motor control system, switching element driving circuits are connected to respective base circuits of four switching elements arranged to form a bridge circuit which has a DC motor connected thereto as an electric load thereon, and an output signal interlocking circuit is provided in each paired driving circuits associated with the corresponding paired switching elements which are connected in series across a DC power source, respectively, thereby preventing simultaneous conduction of each paired switching elements. By virtue of the provision of the output signal interlocking circuits, it is possible to realize a PWM control system for DC motors with a simplified circuit construction and yet to thereby prevent power source short-circuiting trouble with elevated safety and reliability.