A sample-and-hold circuit including an operational amplifier configured to output a result signal to the ADC; a feedback capacitor connected between an input terminal and an output terminal of the operational amplifier to form a feedback path; a plurality of sampling capacitor blocks each connected to one of a plurality of channels and configured to sample and hold an analog signal input to each of the channels; a plurality of controllers each connected between one of the sampling capacitor blocks and the operational amplifier; and a reset unit connected between a reference voltage source and the input terminal of the operational amplifier to reset the operational amplifier when the operational amplifier does not perform a holding operation. The plurality of controllers configured to switch the sampled signal so that held signals for the respective channels are sequentially input to the operational amplifier.