Investigation of lightning discharges has about 250 years history. During these 250 years we have accumulated the knowledge, and the understanding of lightning physics has been done qualitatively. According to the author's understanding our interpretation and understanding about lightning physics is not sufficient. Moreover still we have newly discovered phenomena related with lightning discharge, like discharges from thundercloud top to the ionosphere named RedSprite. The investigation on lightning physics can be concluded as one of the attractive subjects, though it has long history.