Abstract: The present disclosure discloses an optical fiber welding machine, including a device for butt joint of the optical fiber's core. The said device comprises a base and a number of units with V-shape groove. The base and the units are shaped respectively. The said units are mounted on the base fixedly. Comparing with the traditional overall molding device for butt joint of the optical fiber's core, the disclosed embodiment spats said traditional device, which has complicated structure and high accuracy requirements, into a base and a number of V-shape groove units, thus simplifies the shape of the components, which are shaped respectively, so as to facilitate the purpose of molding mould and shaping components, and then the v-shape groove units are mounted on the base. After completion of assembly, a v-shaped slot is grooved on top of each v-shape groove unit to ensure enough precision. The disclosed embodiment reduces both the mold manufacturing cost and the molding cost of components.