To provide a power supply system for disaster time which can easily supply the stable predetermined power to a motor load at a disaster site.

The disaster time power supply system comprises a small-sized gas turbine 2, a fuel supply unit 4 for supplying fuel to the turbine 2, a permanent magnet field type three-phase AC generator 3 coupled to the turbine 2 and driven by the turbine 2, and an autotransformer 7 for regulating a level of an AC output voltage from the generator 3. Thus, the AC voltage output level-regulated by the auto-transformer 7 is supplied to the motor load.