To provide an ion generator capable of reducing the production cost due to urethane resin P which is unnecessarily injected into a space between the circuit substrate 4 and the bottom of the casing 2 and the number of components by eliminating an optional shield to shut off noises from a discharging electrode in the conventional ion generator.

An electrode storage section 21 recessed toward the inside of the casing 2 is provided to contain discharging electrodes 31 and 32. The electrode storage section 21 is isolated from the inside of the casing 2 to prevent invasion of urethane resin P from the inside of the casing into the electrode storage section 21. The discharging electrode 31 is formed box-shaped to enclose the discharging electrode 32 and made to work as a shield.