A voltage pumping device is disclosed. The device may include a voltage level detector for detecting a level of a voltage fed back thereto and generating a voltage pumping enable signal according to the detected voltage level, an oscillator for operating in response to the voltage pumping enable signal and generating a desired pulse signal in a normal operation mode, a clock supply controller for receiving an external clock signal, operating in response to the voltage pumping enable signal and outputting the external clock signal in a low-power operation mode, and a voltage pump for performing a voltage pumping operation in response to the pulse signal from the oscillator in the normal operation mode and performing the voltage pumping operation in response to the clock signal from the clock supply controller in the low-power operation mode.