A reference voltage circuit includes a first amplifier, a first load device and a first PN junction device, second and third load devices and a second PN junction device, an offset voltage reduction circuit, a coupling node potential takeout circuit, and an area adjustment circuit. The offset voltage reduction circuit is configured to reduce an offset voltage between the first and second input terminals at the first amplifier, and the coupling node potential takeout circuit is configured to take out potentials of the first and second coupling nodes. The area adjustment circuit is configured to adjust an area of the second PN junction device in accordance with the potentials of the first and second coupling nodes which are taken out by the coupling node potential takeout circuit.