To provide a detection circuit of impedance or capacitance that can accurately detect minute impedance and is suited for detecting capacity in a capacity-type sensor such as a condenser microphone.

In a capacitance detection circuit 10 comprising a capacity detection section 1 and a capacity cancellation section 2, the capacity detection section 1 comprises an AC voltage generator 11, a first operational amplifier 14 where a non-inverted input terminal is connected to the ground, a second operational amplifier 16 for composing a voltage follower, a detection capacitor 15 connected between the output terminal of the first operational amplifier 14 and the non-inverted input terminal of the second operational amplifier 16, and the like. The capacity cancellation section 2 comprises a third operational amplifier 30 for inverting and amplifying an AC signal from the AC voltage generator 11, and a cancellation condenser 33 connected between the output terminal and the non-inverted input terminal of the second operational amplifier 16. A capacitor 17 under test is connected between the non-inverted input terminal of the second operational amplifier 16 and the ground.