Abstract: The device for non-destructive repair of a side inlet pipe of a main sewer of a sewer system or of a draining pipe in general comprises a repair coating element impregnated with thermosetting resin and slotted onto an inflatable positioning balloon connected to a longitudinal moving element that can be actuated manually along the side pipe, the coating element having a first tubular portion that can be shaped to the inner wall of the side pipe for its repair and a second portion that can be shaped to the inner wall of said main sewer about the outlet hole of the side pipe to ensure the correct positioning of the first tubular portion and to avoid it slipping off after positioning.