Abstract: For the continuous manufacture of optical modules incorporating optical fibres placed within a metal tube and embedded in a sealing product, the fibres (F) are introduced into a rectilinear guide tube (10) and the metal tube (T) is progressively formed around said guide tube from a tape or ribbon (R). The metal tube is then welded along the joint line slightly upstream of the front end of the guide tube (10). In order to permanently check the length ratio between the fibres and the metal tube in the thus obtained optical module, the fibres are introduced into the guide tube at a speed determined in real time on the basis of the measured values of the tensile force exerted on the welded tube, the speed of movement and the temperature of said tube. The sealing product (G) is injected into the welded tube slightly downstream of the front end of the guide tube (10) at a controlled flow rate so as to ensure a complete and non-excessive filling of the metal tube.