A voltage regulator that outputs, from an output terminal, as an output voltage, a power supply voltage that is input from an input terminal, the voltage regulator including an error amplifier that includes a constant current source that causes a current that is based on a constant current supplied from an outside to flow, and outputs a signal that is based on a difference between a feedback voltage obtained by dividing the output voltage and a reference voltage, an output transistor that has a source connected to the input terminal, a drain connected to the output terminal, and a gate connected to an output of the error amplifier, a capacitor that has one end connected to the output terminal, a boost transistor that is connected in parallel with the constant current source and that has a gate connected to another end of the capacitor, and a diode that has an anode connected to the other end of the capacitor and a cathode connected to a ground terminal.