A switching regulator that includes an inductor, a first step-down switch to store charge in the inductor, a second step-down switch to discharge the charge, a first step-up switch to store charge in the inductor, a second step-up switch to discharge the charge, a reverse current detector to detect a reverse current from an output terminal to the inductor through the second step-up switch, or an indication of the reverse current, based on a detection voltage, and a controller to control the first and second step-down switches, and the first and second step-up switches to output a predetermined constant voltage, and to shut off the second step-up switch to make shutdown condition when the detector detects the reverse current or an indication of the reverse current. The reverse current detector may have a threshold value in the step-down operation that is different from a threshold value in the step-up operation.