Abstract: A thermo-sensitive flow sensor includes a bridge circuit, an amplifying circuit and a sensor drive circuit. A bridge circuit adjusting amplifier is further provided and is connected to an output side of the sensor drive circuit for receiving an output therefrom. The output of the sensor drive circuit is adjusted via the bridge circuit adjusting amplifier and is fed back to the bridge circuit so that the balance adjustment of the bridge circuit is automatically performed based on the value fed back to the bridge circuit. An offset voltage adjusting amplifier may be provided instead of, or in addition to, the bridge circuit adjusting amplifier and is connected to the output side of the sensor drive circuit for receiving the output therefrom.