A voltage regulator 10 includes: a level shifting circuit unit 14 shifting a first voltage, which is a voltage level of a first power source 12, to a target value of a second voltage to output the shifted first voltage; a voltage-to-current converting circuit unit 20 varying a magnitude of an output current to output the current while changing a direction of a current using a variable power source 22 varying a voltage to larger and smaller values than a center voltage of an arbitrarily variable voltage range; and an adder-subtracter circuit unit 32 having a first terminal on one side, the first terminal being connected to an output terminal of the level shifting circuit unit, and a second terminal on the other side, the terminal being connected to a resistance element disposed between the second terminal and an output terminal, the resistance element allowing an output current of the voltage-to-current converting circuit unit to flow therethrough as a bias current, wherein a second voltage V.sub.2 is output from an output terminal 42.