An ion diffusing apparatus is disclosed which can maintain a stable ion supplying capability. In the ion diffusing apparatus, the ion generator is detachable for easy maintenance and can deliver the positive ions and negative ions to a remote position while uniformly generating positive ions and negative ions. The ion diffusing apparatus includes an ion generator housing which houses the generator so that a positive ion generating part and a negative ion generating part are provided separately in a direction crossing a flow direction of a stream from a fan, and an ion generating surface is exposed which conforms to a stream flow surface of a stream flow passage extended from the fan to a supply opening. The ion generator may also be a cartridge which has an ion generating surface shaped to conform to the stream flow surface of the stream flow passage.