Irrigation pipe including a pipe having at least a longitudinal row of delivery holes arranged at predetermined distances and communicating with a dripping unit provided inside the pipe, and further having an inlet communicating with the inside of the pipe and an outlet communicating with at least one delivery hole. The inlets or outlets of some or all of the dripping units communicate with the inner space of the pipe or with some or all of the delivery holes through an inlet collecting channel or an outlet collecting channel or segments thereof.