An ion generating device (1) includes: a discharge electrode (21,22), protruding from a surface of the ion generating device, for generating ions by electric discharge, the discharge electrode having (i) a tip part (31) including a brush-like electrically conductive member and (ii) a base end part (33) to which the brush-like electrically conductive member is attached, and the base end part protruding from the surface of the ion generating device for a length (L2) that is longer than a length (L1) of the tip part.