An electrostatic capacitance detection circuit 10 comprises an AC voltage generator 11, a first operational amplifier 14 of which non-inverting input terminal is connected to specific potential (a ground in this example), a second operational amplifier 16 that includes a voltage follower, a resistance (R1) 12 connected between the AC voltage generator 11 and an inverting input terminal of the first operational amplifier 14, a resistance (R2) 13 connected between the inverting input terminal of the first operational amplifier 14 and an output terminal of the second operational amplifier 16, and an impedance element (a capacitor) 15 connected between an output terminal of the first operational amplifier 14 and a non-inverting input terminal of the second operational amplifier 16, and a capacitor to be detected 17 is connected between the non-inverting input terminal of the second operational amplifier 16 and specific potential. The electrostatic capacitance detection circuit 10 and the capacitor 17 are located adjacently.