A booster circuit includes a pump circuit that boosts a voltage supplied from a power supply and outputs the boosted voltage, and a pump controlling circuit that outputs a first clock signal for operating the pump circuit to control the operation of the pump circuit. The pump controlling circuit controls the pump circuit to reduce a number of active charge pump circuits according to an output signal of one of a first comparator and a second comparator, controls the pump circuit to reduce a frequency of a second clock signal for operating the active charge pump circuits by reducing a frequency of the first clock signal according to the other output signal of one of the first comparator and the second comparator, and brings the pump circuit into an inactive state according to an output signal of a third comparator.