The utility model relates to a steel welding device, and in particular to an automatic welding device for H-shaped  steel welds. A trackless automatic welding device for the main weld of an H-shaped steel comprises a trolley with  four wheels, a vertical bracket is provided on the trolley, a welding machine including a control part and a welding  machine head is horizontally installed on the bracket, the welding machine head and the bracket form an angle of 45 degrees, and it also comprises a horizontally arranged side wheel, and the side wheel is connected to the bracket through a horizontal connecting rod. The utility model does not need to set up a platform, reduces unnecessary interruptions during welding, improves weld quality, and improves construction efficiency.