An electricity generating and air conditioning system with a dehumidifier. The system includes an engine, a generator connected to an output shaft of the engine to generate electricity, a heat pump type air conditioner, through which a refrigerant is circulated, the heat pump type air conditioner comprising a compressor, a directional valve, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger, an indoor dehumidifying agent body to dehumidify indoor air, an indoor regeneration heater to regenerate the indoor dehumidifying agent body, and a waste heat recovering means to supply waste heat of the engine to the indoor regeneration heater, and thus, to allow the indoor regeneration heater to use the supplied waste heat as a heat source for the regeneration of the indoor dehumidifying agent body, or to supply the waste heat of the engine to the refrigerant of the heat pump type air conditioner, so that the system exhibits maximal efficiency.