To eliminate the necessity of complex construction work, to enable easy installation in the existing building of a one-floor type structure and to reduce costs when a horizontal shaft pump is removed to installed a vertical pump.

This pump transmits the output rotation of a horizontal shaft motor to the main spindle 2 of a horizontal shaft motor driving type vertical shaft pump via a reduction gear 35 installed in the side of a discharge curved pipe 6. The reduction gear 35 is provided with a gear reduction gear having a spur gear string 36 engaged by having a vertical axis parallel to the main spindle 2, a horizontal input rotary shaft 37 connected to the horizontal output rotary shaft of the horizontal shaft motor, and an orthogonal transformation transmission mechanism 38 for transmitting the rotation of the input rotary shaft 37 to the spur gear string 36. The reduction gear 35 and the horizontal shaft motor are installed in the side of the discharge curved pipe 6, and the axes of the output rotary shaft and the input rotary shaft 37 are set to be orthogonal on a projection plane with respect to the draining direction F of the discharge curved pipe 6.