An air conditioning system with an electrostatically atomizing function includes an electrostatically atomizing unit and a ventilation duct which flows conditioned air. The electrostatically atomizing unit generates a mist of charged minute water particles. The electrostatically atomizing unit is provided with a discharge port which locates adjacent to an air outlet of the ventilation duct. The mist of the charged minute water particles flows into an airflow which is sent from the ventilation duct. The mist of the charged minute water particles effectively spreads to the space by the air flow without dissipating inside the ventilation duct.