A sample/hold apparatus includes first, second and third power supply terminals to which first, second and third power supply voltages are applied. The second power supply voltage is an intermediate voltage between are first and third power supply voltages. A sampling switching element is adapted to pass an input voltage at an input terminal therethrough in response to a sample/hold voltage at a sample/hold terminal. A capacitor has a first terminal connected to an output of the sampling switching element and a second terminal connected to the second power supply terminal. A buffer amplifier is adapted to perform an impedance conversion upon a voltage at the first terminal of the capacitor to generate an output voltage at an output terminal. The buffer amplifier is powered by the first and third power supply voltages.