A voltage regulator, which generates and outputs a given voltage based on a preset reference voltage, includes: a detection circuit part detecting the output voltage and generating and outputting a voltage based on the detected voltage; first and second operational amplifiers each comparing the output voltage of said detection circuit part and the preset reference voltage and outputting a voltage representing a comparison result, the first operational amplifier being controlled based on control signals supplied externally and consuming a larger amount of electric current than the second operational amplifier; and an output circuit part comprising an output transistor outputting an electric current based on the output voltages of the first and second operational amplifiers.