A high voltage generation circuit for a semiconductor memory device comprising a high voltage detector for detecting a high voltage, a ring oscillator for generating a pulse signal in response to an output signal from the high voltage detector when a power-up signal is made active, a high voltage pump circuit for performing a charge pumping operation to generate the high voltage and transfer the generated high voltage to a high voltage output terminal, and a pump controller for controlling the charge pumping operation of the high voltage pump circuit in response to the pulse signal from the ring oscillator. The high voltage generation circuit further comprises an operating voltage detector for detecting whether an external voltage from an external voltage source has an operating voltage level, a burn-in test voltage detector for detecting whether the external voltage from the external voltage source has a level higher than the operating voltage level, a switching circuit for transferring the external voltage from the external voltage source to the high voltage output terminal, and a driver for selectively driving the high voltage detector and the switching circuit in response to output signals from the operating voltage detector and burn-in test voltage detector.