<p>In order to extend the life of electrodes in an ion generator, and to reduce the amount of dust and microparticles that can become attached or accumulate, this ion generator is provided with a ion-generating element that generates ions by generating a corona discharge between a first needle electrode and a second needle electrode. The ion generator alternately switches between a state in which positive ions are generated by the ion-generating element by using the first needle electrode as a discharge electrode and using the second needle electrode as an induction electrode, and a state in which negative ions are generated by the ion-generating element by using the second needle electrode as a discharge electrode and using the first needle electrode as an induction electrode.</p>
