A regulator includes a variable resistance unit coupled between an input node to which a pumping voltage is inputted and a control node and configured to adjust resistance of the variable resistance unit in response to a control signal varied depending on a target voltage, a voltage output unit configured to adjust the pumping voltage according to potential of the control node and output the adjusted pumping voltage, and a regulation unit configured to control the potential of the control node according to the adjusted pumping voltage, to output the target voltage. The regulator adjusts the resistance of an internal resistor according to the target voltage, thereby reducing current consumption.