The invention relates to a method and to a device for producing vacuum tubes for solar thermal installations, wherein the vacuum tube comprises an outer tube and an inner tube arranged within the outer tune, and the gap between the outer tube and the inner tube is sealed with respect to the exterior and evacuated. An outer tube (4) is coated in a first vacuum unit (1) and an inner tube (5) is coated in a second vacuum unit (2). The coated outer tube (4) and the coated inner tube (5) are assembled in a third vacuum unit (3) and fused together at the ends. The third vacuum unit is connected to the first vacuum unit (1) and to the second vacuum unit (2), such that the outer tube (4) and the inner tube (5) are not exposed to the atmosphere throughout the entire production of the vacuum tubes.