An operational amplifier includes an input stage with a first main input unit, a first auxiliary input unit, a second main input unit and a second auxiliary input unit, an amplification stage with a first current mirror receiving currents from the first main input unit and the first auxiliary input unit, and a second current mirror receiving currents from the second main input unit and the second auxiliary input unit, an output stage receiving voltages from the first current mirror and the second current mirror, a voltage storage unit storing an intermediate voltage based on an output signal generated by the output stage during at least one of a first operation period and a second operation period, and a switching unit that differently controls a first feedback path between the output stage and the input stage and a second feedback path between the output stage to the voltage storage unit in accordance with the first operation period and the second operation period.