A disclosed operational amplifier circuit with a multi-stage amplifier configuration provides fast-response and high withstand-voltage characteristics without using high withstand-voltage transistors as output transistors in its amplifying stages. The output voltage range of a differential amplifier circuit in a first stage is limited by voltage clamping based on a reverse withstand voltage of a bipolar diode. The output voltage range of an amplifier circuit in a second stage is limited by voltage clamping based on a reverse withstand voltage of another bipolar diode. A constant voltage circuit and an apparatus including such an operational amplifier circuit are also disclosed.