A DC/DC converter includes a switching element which is opened and closed to supply power from an input power supply V.sub.cc through a coil to an output terminal, which is connected to a load, and to adjust the voltage at the output terminal. The DC/DC converter also includes a coil current detection resistor arranged to detect a coil current, a smoothing capacitor connected to the load side of the coil current detection resistor and arranged to smooth the voltage at the output terminal, a reference current value control circuit arranged to detect the voltage on the coil side of the coil current detection resistor to control a reference current value of the coil current, a clock generator arranged to generate a reference clock, and a feedback circuit arranged to close the switching element in synchrony with the reference clock and to open the switching element when the coil current exceeds the reference current value.