A waveform shaping circuit includes a first parallel circuit including a first capacitance element and a first resistance element coupled in parallel with each other, a positive pulse voltage being applied to a first terminal of the first capacitance element and a second terminal of the first resistance element, a gate terminal of a field-effect transistor being electrically coupled to a third terminal of the first capacitance element and a fourth terminal of the first resistance element, a first Zener diode having a first anode coupled to the third terminal and the fourth terminal, and a second parallel circuit including a second capacitance element and a second resistance element coupled in parallel with each other, a first cathode of the first Zener diode being coupled to a fifth terminal of the second capacitance element and a sixth terminal of the second resistance element.