Abstract: A sensor detection signal extracting circuit comprises a sensor, a control voltage generator, an adder, an amplifier, and a low-pass filter. The control voltage generator comprises two input terminals to one of which a voltage is applied based on the voltage source of the sensor. The output of the control voltage generator is added to the output of the sensor by the adder. The output of the adder is amplified by the amplifier, and its output is outputted to the output terminal and applied to the other input terminal of the control voltage generator through the low-pass filter. As a result, two loop systems are formed, that is, one loop for offsetting the change in the voltage of a voltage source applied to the sensor, and the other loop for offsetting a low frequency change such as that due to change in the environmental temperature. Therefore, the true output of the sensor can be obtained at the output terminal with little effect by the voltage change of the voltage source or by change in temperature.