To provide a helical pipe for a steep slope able to regulate the state of an uneven surface according to the degree of a steep slope.

A helical pipe for a steep slope is formed that a belt-like member 1 formed that a rib 15 is erected on one surface of a belt-like board 11 and engaging joints 12 and 14 are arranged in the vicinity of two side ends thereof 11 is helically wound around the joints 12 and 14 of the adjoining belt- like board 1 are engaged and joined together. A substance where a recessed groove and a protrusion or a step part 13 are formed along a longitudinal direction on the other surface side of the belt-like board 11 is used as the belt- like member 1. The belt-like member 1 is helically wound such that the other surface side of the belt-like board 11 is positioned on the inner side, and an uneven surface is formed in an inner surface.