PURPOSE: To reduce the chip area by varying the amplification factor of part of or all of an operational amplifier so as to change the characteristic.

CONSTITUTION: A capacitor integration device consists of capacitive elements Co, Cf, switches SW1, SW2 and an operational amplifiers Ampl and the transfer function of the switched capacitor integration device is changed by making the amplification factor A of the operational amplifier variable. That is, even when the capacitance ratio α of the switched capacitor integration device is made fixed, the amplification factor A of the operational amplifier is changed to relatize the switched capacitor integration device having the same characteristic as the case in changing the capacitance ratio of a conventional switched capacitor integration device.