Abstract: A welding head carrier for use in welding the inner surface of a tube includes inter alia a welding head provided with a welding torch and a camera, a wireless camera mounted at the inner side of the tube to monitor whether cables are entangled, a wireless receiver for receiving wirelessly an image from the wireless camera, including a camera controller for controlling the camera and the wireless receiver, display for displaying the welding operation and the inside of the tube. Fixing units can be adjusted in length depending on the size of the tube, thus eliminating the need for the rebuilding or replacement of the welding head carrier, leading to cost savings. The welding head can be easily mounted, regardless of size and configuration of the welding head, and the range of use of the welding head carrier can be extended.