A voltage generation circuit of a semiconductor memory apparatus includes a plurality of pumping units configured to provide voltages to an output node; a sensing unit configured to sense a voltage level of the output node and generate a pumping enable signal; an oscillator configured to generate an oscillator signal in response to the pumping enable signal; and a control unit configured to selectively output the oscillator signal to the plurality of pumping units in response to an active signal, a power-up signal and a mode register set signal.