A transmission shaft protecting device of a paddle wheel aerator includes a base having a through hole, a bearing assembly located inside the through hole, and a holding assembly arranged on two sides of the base with through hole for clamping the bearing assembly and the transmission shaft. This device can be useful for solving the issue of transmission shaft wearing and enhancing the stability of the dynamic assembly of the aerator.一種用於水車式增氧機之傳動軸保護裝置,包含一基座,於基座上設有一通孔;一軸承組件,配置於通孔內;及一固定組件,固定於通孔兩側之基座上,用以夾固軸承組件以及穿設於軸承組件及固定座之傳動軸,以有效地解决水車式增氧機之傳動軸磨損問題、增加增氧機動力組件穩定性。401‧‧‧支撐架402‧‧‧軸承組件403a‧‧‧固定環架403b‧‧‧調整座403c‧‧‧調整螺桿405‧‧‧傳動軸407‧‧‧螺帽408‧‧‧圓形隔片409‧‧‧O型環
