Provided is a band gap reference voltage circuit having an improved power supply rejection ratio. Owing to a voltage supply circuit (51), a power supply voltage (V5) does not depend on variation of a power supply voltage (Vdd). A voltage (V3−V2) which is generated across a resistor (41) and has a positive temperature coefficient is determined based not on the power supply voltage (Vdd) but on the power supply voltage (V5), and hence the voltage (V3−V2) does not depend on the variation of the power supply voltage (Vdd). As a result, the power supply rejection ratio of the band gap reference voltage circuit is improved.