PURPOSE: To prevent the chemical erosion of a connection head part and the mechanical cavitation by installing a cap-shaped collar which covers the connection head part and has a through hole at the center part and has an equal sectional shape and is made of the metal having a high strength and high erosionproofness, at the connection head part arranged at the edge part of an injection pipe.

CONSTITUTION: As for a high pressure fuel injection pipe 1, a connection head part 2 having a truncated conical shape outside the axis center is arranged on one side or both side edge parts. A sleeve pusher 4 is installed at the neck lower part of the connection head part 2, and a tightening nut 5 in connection is assembled. In this case, at the connection head part 2, a cap-shaped collar 3 which covers the connection head part 2, has a through hole 3' at the center part and an equal sectional shape and is made of the metal material having a high strength and high erosionproofness is applied and engaged with the connection head part 2. Accordingly, the chemical erosion on the pressing surface including the top edge surface of the connection head part 2 and the generation of the mechanical cavitation can be effectively lightened and prevented. Further, the volume of the connection head part 2 is reduced by the volume portion of the cap-shaped collar 3, and an annular recessed groove on the inner peripheral surface of a flow hole 1' is made shallow.