To solve a problem that vibration of a rocker arm mounted to a side wall 4a of a cylinder head 4 and a noise resulting therefrom are generated when the vibration on a fuel injection nozzle 2 side is directly transferred to the side wall 4a through a nozzle pressing arm 1.

The nozzle pressing arm 1 comprises a base part 1C secured to the cylinder head 4 and a first arm part 1A abutting to an end 2B on the opposite to the cylinder head side of the fuel injection nozzle 2 in a position offset from the fuel injection nozzle 2 toward one side wall 4a side of the cylinder head 4. The nozzle pressing arm 1 also comprises a second arm part 1B abutting to a supporting shaft 8 secured to the cylinder head 4 in a position further offset from the base part 1C toward the side wall 4a side. The supporting shaft 8 is spaced from one side wall 4b of the cylinder head 4.