A disclosed forming system is a forming system which expands and forms a metal pipe in a die. The forming system includes a preliminary forming apparatus which preliminarily forms a metal pipe material, a forming apparatus which includes a gas supply unit which supplies gas into the preliminary-formed and heated metal pipe material to expand the metal pipe material and a main body portion to which the die is attached, and a cutting device which cuts at least a portion of the formed metal pipe. The gas supply unit is provided so as not to be disposed on a first straight line which connects the preliminary forming apparatus and the main body portion in a plan view and a second straight line which connects the cutting device and the main body portion in a plan view.