A power supply apparatus of the present invention comprises: a constant voltage generation section (first DAC (21), second DAC (22), resistor (R2), resistor (R3)) that generates a positive constant voltage (Va); a pulse voltage generation section (pulse oscillator (23), amplifier (24)) that generates a positive pulse voltage (Vb); a capacitor (C1) of which one end is connected to the output terminal of the pulse voltage generation section; and a diode (D1) of which an anode is connected to the other end of the capacitor (C1), and of which a cathode is connected to the output terminal of the constant voltage generation section. A positive-negative bipolar pulse voltage (Vc) is outputted from the other end of the capacitor (C1). Thus, it is possible to generate a positive-negative bipolar pulse voltage with a simple and small-scale circuit configuration.