An ion generator is capable of efficiently generating ions and includes a case accommodating an ion-generating element that generates ions by discharging electricity from a discharging needle electrode and a cover having openings for ion discharge. Resistive elements are disposed at peripheral portions of the openings, and the resistive elements are grounded. Since the resistive elements are grounded, the peripheral portions of the openings are prevented from being electrostatically charged. As a result, retention of ions at the openings is suppressed, and ions are efficiently generated and discharged.