PURPOSE: To simplify the constitution of a switched capacitor circuit by connecting a capacitor between the common connecting point of the first serial body and the common connecting point of the second serial body.

CONSTITUTION: One end of the first serial body in switches 1 and 2 is connected to a first input terminal 9 and one end of the second serial body in switches 3 and 4 is connected to a second input terminal 10. Then, an input capacitor 5 is connected between the respective common connecting points. In the first period, switches 1, 3 and 7 are turned-ON and an electric charge corresponding to a difference voltage between the terminals 9 and 10 is accumulated in the capacitor 5 and an electric charge accumulated in an integral capacitor 8 is discharged. Next, in the second period, the switches 1, 3 and 7 are turned-OFF and by this turn-OFF, the electric charge accumulated in the capacitor 5 is transferred to the capacitor 8. Then, the voltage of difference between the terminals 9 and 10 is outputted to a terminal 11. Thus, the difference voltage of the input voltage can be sampled by the single capacitor and the constitution of the circuit is simplified.