A voltage smoothing circuit is configured to smooth a voltage outputted from a power supply portion. The voltage smoothing circuit includes first and second smoothing capacitors, a first balancing resistor, and a second conduction regulating portion. The first smoothing capacitor and the second smoothing capacitor are connected in series to each other and are connected in parallel to the power supply portion. The first balancing resistor is connected in parallel to the first smoothing capacitor. The second conduction regulating portion is connected on a current path in parallel with the second smoothing capacitor and conducts current in one direction on the current path in a case where a voltage equal to or greater than a second predetermined voltage has been applied.