The invention relates to a novel spiral gas tube forming machine, which is applicable for spiral ducts formed by rolling strip steel roll material along a spiral involute track. The spiral gas tube forming machine comprises a frame (1); a material shelf (2), a lock forming set (3), a mold frame (4) and a cutting machine (5) arranged on the frame (1); and a discharge shelf (7) arranged on the front side of the cutting machine (5); wherein the frame (1) comprises a bottom plate (1.1), level adjusting bases (1.2), material shelf guide rails (1.3) and a platform (1.4); the material shelf (2) comprises a slider (2.1), a pillar (2.2), a main body (2.3) and a connection crank arm (2.5); the lock forming set (4) comprises a bottom plate (3.1), wall plates (3.2), a feed leveling device (3.3), an upper and a lower rib-pressing rollers (3.4), an upper and a lower roller groups (3.5), a discharge guide plate (3.6), an upper and a lower engagement wheels (3.7), and a pressing crank arm (3.8); and the mold frame comprises a support frame (4.1), guide rails (4.2), a template (4.3) and wind pipe baffles (4.5). The spiral gas tube forming machine has the advantages of simple structure, integration of the material shelf and the machine, good lock formability, multi-purpose of the mold frame, synchronous cutting without stopping, high production efficiency and good product quality.