To reduce a vibration of a common rail and a noise vibration in each part caused by the vibration of this common rail.

A groove part 16 is formed along a longitudinal direction of an engine in a side surface 15 abutting to an intake manifold 12 of a cylinder head 11, a similar groove part 18 is formed in a surface 17 in a side of the intake manifold 12 opposed to this groove part 16. These groove parts 16, 18 are formed respectively in almost semicircular sectional shape, in a condition confirming to each other, an almost circular space is generated. A columnar common rail 19 is arranged in these groove parts 16, 18, interposed between the cylinder head 11 and the intake manifold 12 fastened to each other by axial tension generated by a stud bolt 13 and a nut 14, and firmly fixed. By firmly fixedly holding the common rail 19 over its almost full length, a vibration is suppressed.