A double-sided simultaneous welding system is disclosed. The double-sided simultaneous welding system comprises: a first welding device installed in a first side of a welding object; a second welding device installed in a second side of the welding object which does not contact with the first side; and a control unit controlling to perform welding of a welding area where the first and second welding devices shares in a direction of the first and second sides of the welding object, respectively.
