Provided is an end seal structure of a fuel rail for a gasoline direct injection engine, the fuel rail being constructed and arranged such that an end or both ends of a rail body composed of a tubular body such as a pipe is/are closed by an end cap or end caps, the end seal structure having a simple structure that does not need to provide a thicker fuel rail, making it possible for the end cap portion to meet higher pressure requirements. The end seal structure is characterized in that: a collar is joined by brazing to an outer circumference of an end of a pipe of the rail body including a pipe; the end cap having a cap-nut shape and including a sealing projection on an surface thereof facing the opening at the end of the pipe of the rail body, is screwed and fixed to the collar; and the sealing projection of the end cap brings into pressure contact with the end of the opening of the rail body by an axial force created by tightening of the end cap having the cap-nut shape to seal the end of the opening of the
