Abstract: Since a reduction gearbox (50) is mounted onto the outer wall of the discharge elbow (30), the installation height of a vertical axis pump is reduced. A pump shaft (34) comes out the outer wall of the discharge elbow (30) and passes through a separate wall (36) provided above the outer wall of the discharge elbow (30). An air space (40) is formed between the separate wall (36) and the outer wall of the discharge elbow (30). The air space (40) is open through and through to the atmosphere. A casing (76) for the reduction gearbox (50) is formed including the separate wall (36) and the outer wall of the discharge elbow (30). The reduction gearbox (50) is mounted onto the discharge elbow (30) in a one-piece construction. An output stage gear (54) of a gear train of the reduction gearbox (50) is mounted onto the pump shaft (34) comes out through the outer wall of the discharge elbow (30). An input shaft (52) of the reduction gearbox (50) comes out in the horizontal direction and is connected to a driver (86).