A voltage generator adapted for a flash memory is disclosed. The voltage generator includes a charge pump circuit and a voltage regulator. The charge pump circuit includes at least one charge pump unit having a voltage receiving terminal and a voltage transmitting terminal. The voltage receiving terminal receives a reference voltage and the voltage transmitting terminal generates an output voltage. The charge pump unit includes first and second voltage transmitting channels and first and second capacitors. The first and second voltage transmitting channels are turned on or off according first and second control signals, respectively. The first and second capacitors receive the first and second pump enabling signals, respectively. The voltage regulator outputs a regulated output voltage according to the output voltage.