Provided is a voltage regulator in which an output current can be controlled stably and accurately to an overcurrent protection set value without the need of providing a phase compensation circuit including an element having a large area. The voltage regulator includes a constant voltage control circuit including: a first differential amplifier circuit for comparing a first reference voltage and a feedback voltage to each other; and an output transistor to be controlled by an output voltage of the first differential amplifier circuit, and an overcurrent protective circuit including: a resistor for measuring the output current; a second differential amplifier circuit for measuring a difference between voltages at both terminals of the resistor; a comparator for comparing an output voltage of the second differential amplifier circuit and a second reference voltage to each other; and a switch to be controlled by a detection signal of the comparator. When the output current equal to or larger than an overcurrent protection set value flows, the output voltage of the second differential amplifier circuit is input to the first differential amplifier circuit via the switch, to thereby switch control of the output transistor from control based on the constant voltage control circuit to control based on the overcurrent protective circuit.