A switching power supply includes: a switching output circuit configured to generate an output voltage from an input voltage by charging a capacitor by turning on and off an output transistor; a control circuit configured to halt the driving of the switching output circuit when charging electric charge to the capacitor per switching event is limited to a lower limit value and the output voltage, or a feedback voltage commensurate therewith, is raised from a predetermined reference voltage; and a lower limit value setting circuit configured to variably control the lower limit value during the driven period of the switching output circuit. For example, the lower limit value setting circuit can increase the lower limit value with increase in the number of times of switching.