A power supply circuit including a DC/DC converter having switching elements and configured to receive an input voltage in an input line and generate an output voltage in an output line; and a linear regulator configured to receive the output voltage and supply a stabilized voltage to a load. The DC/DC converter switches between a switching mode to switch the switching elements and a bypass mode to put a switching element existing on a path from the input line to the output line, of the switching elements, in a full-on state and stop switching of the other switching element.