A voltage supply apparatus for supplying a voltage to a detection circuit, including a power supply filter (4) and a control section (5) which supply a sensor drive voltage Vbg to a sensor device (2) having a ratiometric characteristic. The power supply filter (4) has supply paths PL1 and PL2. The control section (5) determines whether or not a switching determination time has elapsed after startup. In the case where the switching determination time has not yet elapsed, the power supply filter (4) supplies the sensor drive voltage Vbg through supply path PL1. In the case where the switching determination time has elapsed, the power supply filter (4) supplies the sensor drive voltage Vbg through supply path PL2. The response of the sensor drive voltage Vbg to a variation in power supply voltage Vcc is slower when supplied through the supply path PL2 than through the supply path PL1.