A voltage transforming apparatus includes a first high voltage side coil, a first low voltage side coil magnetically coupled to the first high voltage side coil, a second low voltage side coil magnetically coupled to the first high voltage side coil, and a first switch switching an externally supplied voltage between being supplied to the first low voltage side coil and the second low voltage side coil and being supplied to the first high voltage side coil. The first low voltage side coil and the second low voltage side coil are provided such that a magnetic flux that is generated by current flowing through the first low voltage side coil and a magnetic flux that is generated by current flowing through the second low voltage side coil cancel each other out when a voltage is supplied via the first switch.