Abstract: A boosting and step-down switching regulator includes one error amplifying circuit, and an output of the error amplifying circuit is compared with a triangular wave for boosting and a triangular wave for step-down different in voltage level from each other but synchronous with each other in comparison circuits, respectively, to switch the boosting operation and the step-down operation over to each other. Thus, the boosting operation and the step-down operation can be readily switched over to each other irrespective of an input voltage and an output voltage.