The present invention is to suppress generation of cavitation in an impeller of a pump and disproportion of generation areas thereof by suppressing a secondary flow generated in a bent portion of a pump suction pipe. A pump suction pipe includes: a suction pipe outlet portion that is connected to an impeller suction port of a pump and is arranged in the up-and-down direction; a suction pipe inlet portion that is arranged in the lateral direction; and a suction pipe bent portion that connects the suction pipe outlet portion and the suction pipe inlet portion to each other and changes a flow from the lateral direction to the up-and-down direction. The distance from a reference point to an inner end of the suction pipe bent portion is monotonically increased from the upstream side to the downstream side on a vertical cross-section.