Abstract: In a radiation type air conditioning system for cooling or heating fluid such as air or refrigerant through heat exchange and supplying the cooled or heated fluid into a radiant panel to radiatively cool or heat a room, the air is cooled by a heat exchanger (evaporator), and the cooled air is supplied onto the radiation face of the radiant panel by a fan to prevent dew condensation on the radiation face of the radiant panel. If the air which is cooled and dried by the evaporator is heated by a heater when it is supplied onto the radiation face of the radiant panel, the dew condensation preventing effect can be enhanced. Further, plural through holes are formed in the radiation panel and the cooled air is blown out onto the radiation face through the through holes, so that the dew condensation preventing effect can be enhanced.