A temperature sensor circuit includes a band-gap reference voltage circuit. The resistor and diode-connected bipolar transistor of the band-gap reference voltage circuit are separated into a transistor-resistor series circuit and a transistor-diode series circuit. The transistor-resistor series circuit is configured such that an emitter of the bipolar transistor Q21 is connected to a power supply voltage terminal VCC, a collector thereof is grounded via the resistor R2. The transistor-diode series circuit is configured such that an emitter of the bipolar transistor Q20 is connected to the power supply voltage terminal VCC, a collector thereof is connected to a collector of the diode-connected bipolar transistor Q19, and an emitter of the diode-connected bipolar transistor is grounded. A voltage divider circuit 5 having a plurality of output terminals is connected to the transistor-resistor series circuit and the transistor-diode series circuit via first and second buffer circuits 3 and 4, respectively.