It is expected to provide an ion generating apparatus and an ion presence determination method that can prevent the lower accuracy of the ion presence determination caused by the humidity effect. The ion generators are switched ON at the different timing, the electrical potential of the collecting electrode is measured to determine that the ion is present (or not present) when the voltage difference is larger (or smaller) than the threshold. A humidity detecting unit is arranged in a duct. The set threshold for the determination is based on the humidity of the humidity detecting unit, and the ion presence determination is not performed when the humidity is equal to or more than a predetermined humidity. When the determination representing no ion is obtained predetermined times, the warning is output for the users with a LED of a display, a buzzer of a controller or the like.
