a method of assembling a vehicle body panel member comprises the steps of coupling each adjacent two of subdivided outer panel components with each other to incorporate the subdivided outer panel components into an outer panel , fixing the outer panel a predetermined position , providing the outer panel fixed at the predetermined position with arc welding at a junction between two adjacent subdivided outer panel components appearing on an external surface of the outer panel , and coupling subdivided inner panel components with the outer panel having been subjected to the arc welding so that the subdivided inner panel components are disposed on the inside of the outer panel to form an inner panel and thereby the vehicle body panel member is obtained .