Abstract: The method consists of introducing the dripper units (1) one after the other inside a conduit (2) while the latter is being formed in an extruder (10), then calibrated in a calibrator (13), heat welding the dripper units (1) to the inner wall (3) of the conduit (2) gradually as it progresses downstream of the extruder (10), then cooling the conduit (2) and perforating it opposite each dripper unit (1) to make it communicate with the exterior. According to the invention, the heat welding operation is executed downstream of the calibrator (13) by pinching the dripper unit and the wall of said conduit between first and second opposing surfaces (20, 22b) one of which is driven at the speed of progression of the conduit (2) and the other is arranged on a fixed support member (16) forming a feed guide for the dripper units (1). The dripper units are presented for the pinching operation one after the other contiguously by their ends.