An object of the present invention is to provide a synthetic resin pipe configured to perform water-stop accurately by forming a part connecting convex portions of an outer pipe to be flat without reducing flexibility in order to compose a synthetic resin pipe having flat inner and outer surfaces. A synthetic resin pipe according to the present invention includes an inner pipe formed by spirally winding a belt-like synthetic resin; a spiral reinforcing part formed by spirally winding a synthetic resin having a projected rim with convex portions projecting outside; an outer pipe of belt-like synthetic resin provided so as to connect a part or all of the convex portions arranged in a pipe axis direction; and a shape retaining material for the outer pipe made of a belt-like metal sheet for retaining a shape of the outer pipe flat and buried in or provide to an inner surface of the outer pipe; wherein the shape retaining material for the outer pipe is a synthetic resin pipe wound around the convex portions of the projected rim at predetermined intervals and connecting the convex portions of the projected rim.