A reference voltage circuit includes: a first and a second NPN transistor having a collector and a base shorted and diode-connected, the second NPN transistor having an emitter connected to a first potential node and operating at a higher current density; a first resistor connected in series with the first NPN transistor; a second resistor having one end connected to a circuit with the first NPN transistor and the first resistor connected in series; a third resistor having one end connected to the collector of the second NPN transistor; a connection point to which the other ends of the second and the third resistor are connected; an arithmetic amplifier circuit having an inverting input terminal, a non-inverting input terminal, and an output terminal respectively connected to the second resistor, the third resistor, and the connection point; and a current supply circuit connected to the collector of the first NPN transistor.