A power generator system, including a first generator and a second generator, a detector detecting a power of the first generator, a determinator determining whether a parallel operation of the first generator and the second generator is necessary based on a detection value detected by the detector when the first generator is operating and the second generator remains unstarted, a power supply unit supplying a starting power to the second generator to start the second generator when it is determined that the parallel operation is necessary, and a generator controller controlling operation of the second generator so as to operate synchronously in parallel with the first generator after the second generator is started.