WELDING DEVICE AND WELDING METHOD

According to some embodiments, there is provided a welding device for welding outer peripheral edges of two irregular shaped plates which are overlapped, including: a rotary table to which the two irregular shaped plates in an overlapped state are fixed; a torch unit, including a welding torch positioned to face the outer peripheral edges of the two irregular shaped plates fixed to the rotary table; a first torch actuator, capable of changing an orientation and a distance of the welding torch relative to the outer peripheral edges; and a first controller, configured to control the first torch actuator, so that the orientation of the welding torch relative to a tangential line of the outer peripheral edges and the distance of the welding torch from the outer peripheral edges are kept constant along a circumferential direction of the outer peripheral edges, during rotation of the two irregular shaped plates.