The present invention relates to a small ultraviolet (UV) irradiation module, at least including a solar panel (or a miniature power generating device) utilizing the photo-electric effect to convert light into electricity and an ultraviolet light-emitting device receiving electricity from solar panel to emit UV light. The present invention further relates to a clothing with the solar panel attached outside to absorb light and the ultraviolet light-emitting device attached inside to irradiate the skin for its efficient stimulation of vitamin D synthesis.
