To improve evaporation efficiency of water, and ensure excellent heat radiation efficiency with a less amount of supply water.

The present apparatus is adapted such that a vertical groove 2 is formed in an outer surface of the heat transfer pipe 11, and drain water flows from a water reception tray into the groove 2. Hereby, the drain water is evaporated on the high temperature heat transfer pipe 11 by a heat dissipation fin 12, whereby evaporation efficiency is improved and hence heat dissipation efficiency becomes excellent. The drain water resembles distilled water so that there are eliminated harms such as corrosion and scaling at respective parts of the air cooled heat dissipation apparatus.