To provide a bandgap reference circuit capable of shortening a start time at power-on in a circuit lowered in power consumption. There is provided a bandgap reference circuit using an op amplifier to generate a reference voltage, which is equipped with a first current source connected between a power supply terminal and an operating current input terminal of the op amplifier, a second current source having one end connected to the power supply terminal, and a switch connected between the other end of the second current source and the operating current input terminal of the op amplifier, and in which a switch is turned on at power-on and turned off after starting of the reference voltage.