The utility model provides a steel pipe welder, consisting of a steel pipe delivering device, a steel pipe guide device, a jointing device, a welding wire delivering device, a welding fluid delivering device, an welding heat position adjusting device, a welding tracking device and a conductivity device; a welding mechanism consisting of the welding wire delivering device, the welding fluid delivering device, the welding heat position adjusting device and the welding tracking device is arrange under a steel pipe transmission line consisting of the steel pipe delivering device, the steel pipe guide device and the jointing device, wherein the welding wire delivering device is in an obtuse-angle bending shape, that is, the welding delivering device is bent at the middle, with a horizontal front half part and a downbent back half part which are bent downward front the bent part; the downbent back half part of the welding wire delivering device is arranged under the steel pipe transmission line and forms an included angle together with the steel pipe transmission line; the welding head of the welding mechanism is arranged at a position where the jointing device is arranged. The steel pipe welder can produce submerged arc welding longitudinal pipes on which seam joint and submerged-arc welding are performed at the same time. The utility model is simple, reliable and low in cost, with the efficiency being two times higher than that of the spiral submerged arc welder group.