A power supply control device for supplying electricity to a plurality of loads includes: a plurality of synchronous rectification type DC-DC converters, each regulating and supplying the power source to the load; a plurality of reference voltage circuits, each outputting a reference voltage; a common reference voltage circuit outputting a common reference voltage; a plurality of comparison circuits, each outputting a signal that corresponds to the difference between a feedback voltage, which is a fraction of the output voltage from the DC-DC converter, and the reference voltage or the common reference voltage; and a common reference voltage circuit controller controlling the common reference voltage circuit so that the common reference voltage falls when the input to the comparison circuit is switched from the reference voltage to the common reference voltage.