A voltage boost circuit and a method of boosting voltage using a voltage boost clock signal with varying frequency, in which the voltage boost circuit includes a boost voltage generator that responds to a voltage boost clock signal in order to boost an input voltage and outputs the boosted input voltage as an output boost voltage; and a boost voltage frequency control unit that responds to the result obtained by comparing a level of the output boost voltage and a level of a target boost voltage so as to change the boost voltage frequency of the voltage boost clock signal and outputs the voltage boost clock signal having the changed boost voltage frequency. The voltage boost circuit and the voltage boosting method can prevent a waste of the operating current during the boosting of the voltage.