Abstract: An irrigation pipe, primarily for subterranean irrigation, said pipe having incisions in the longitudinal direction of the pipe, which incisions will open under the action of the pressure enabling the irrigation water to flow into the surrounding ground. It is characteristic of the pipe that a pipe made of two-layer material is used, the outer part of which is thinner than the inner part and the inner part has been cooled down during the manufacturing before the outer layer has been made, by which method the characteristic can be obtained that the incision opens more on the outside than on the inside thus preventing impurities of any kind from accumulating in the incision.