To solve the problem that hitherto an ion generator as a single unit is installed in a room or the like and ionized air is sent by a blower or the like but diffusion is blocked by attracting actions or the like of fellow ions to each other to obtain only local effect and further the blower generates noise, needs a large size and is expensive.

In an ionized air diffusing system, whole of a room or the like is considered as one ion generator and a minus electrode part is provided at a ceiling part, plus electrode parts are provided at a lower part of a flank, a bottom surface or the like to convert whole of the room space to ionized air. Thereby, natural diffusion of the ionized air can be attained.