Provided is an ion generator that has a potential sensor provided integrally inside the main body of the ion generator, and that can measure, with the potential sensor, an electric field that reaches the potential sensor from a member from which static charge is to be eliminated, without being affected by an electric field between a discharge electrode and an opposing electrode. This ion generator comprises a discharge electrode, an opposing electrode, and a main body part including these electrodes, the ion generator sending out, toward a member from which static charge is to be eliminated, air ions generated by applying a high voltage between the electrodes. A potential sensor that measures the potential of the member from which static charge is to be eliminated is provided integrally to the main body part, and a projecting electrostatic-shielding plate that projects from the main body part is provided between the potential sensor and a discharge part constituted by the discharge electrode and the opposing electrode.