To provide a cylinder head of an internal combustion engine in which a fuel line can be easily and surely provided in the cylinder head without making extensive engineering changes.

A cylinder head 10 is partitioned parallel to an axis of a cylinder 11 at a position including a water jacket 12 and an injector-mounting bosses 16, and the cylinder head 10 comprises a 1st partition 10A and a 2nd partition 10B. In the water jacket 12 on the partition face, a fuel-pipe-installation groove 15 is formed. After the fuel pipe 14 is installed in the groove 15, both the partitions 10A, 10B are welded. Thus, the fuel pipe 14 can be installed in the water jacket 12 in the cylinder head 10 to raise fuel temperature by heat-exchange with engine-cooling water.