Abstract: A power generator includes: an output iron core having an output winding wound therearound; and a field iron core having a main field winding and an auxiliary field winding wound therearound, and is a self-excitation type in which one of the output iron core and the field iron core serves as a stator and the other serves as a rotor, the main field windin is connected to a first rectifying element, the auxiliary field winding is connected to a second rectifying element, and power is generated by relative rotation of the stator and the rotor. The power generator is provided with an initial excitation unit configured to apply, to one or both of the output iron core and the field iron core, a magnetic force to a degree required for initial excitation in power generation.