A forming system for expanding and forming a metal pipe in a die, comprising: a preliminary forming apparatus for preliminary forming a metal pipe material; a forming apparatus which includes a gas supply unit for supplying gas into a 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 for cutting at least a portion of the formed metal pipe, wherein 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; characterized in that in a case where horizontal directions orthogonal to each other with respect to a center of the forming apparatus are a first direction and a second direction, the preliminary forming apparatus and the cutting device are disposed on one side in the first direction from the forming apparatus, wherein the preliminary forming apparatus is disposed on one side in the second direction from the forming apparatus, wherein the cutting device is disposed on the other side in the second direction from the forming apparatus, and wherein the forming system further comprises: a first device for transporting the metal pipe material from the preliminary forming apparatus to the forming apparatus; and a second, device for transporting the metal pipe from the forming apparatus to the cutting device. a preliminary forming apparatus for preliminary forming a metal pipe material; a forming apparatus which includes a gas supply unit for supplying gas into a 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 for cutting at least a portion of the formed metal pipe, wherein 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; characterized in that in a case where horizontal directions orthogonal to each other with respect to a center of the forming apparatus are a first direction and a second direction, the preliminary forming apparatus and the cutting device are disposed on one side in the first direction from the forming apparatus, wherein the preliminary forming apparatus is disposed on one side in the second direction from the forming apparatus, wherein the cutting device is disposed on the other side in the second direction from the forming apparatus, and wherein the forming system further comprises: a first device for transporting the metal pipe material from the preliminary forming apparatus to the forming apparatus; and a second, device for transporting the metal pipe from the forming apparatus to the cutting device. a first device for transporting the metal pipe material from the preliminary forming apparatus to the forming apparatus; and a second, device for transporting the metal pipe from the forming apparatus to the cutting device.