Thin walled compartmented tubular structure and its manufacturing process. The elbow or T-shaped structure, includes an external wall (14)and continuous internal walls (22) made in one piece. This therefore materializes, between the inlet (10) and each outlet (12) of the structure, at least one continuous passage to direct a fluid circulating inside it. The structure according to the invention is manufactured by diffusion welding and superplastic forming, from titanium alloy sheets. One application is for aircraft de-icing circuits.