A valve train for an internal combustion engine is comprised of a
lubricating oil, and a camshaft which is made of an iron-based material
and comprises a cam lobe and a camshaft journal. The camshaft slidingly
moves on a counterpart thereof through the lubricating oil. A hard carbon
film is formed on at least one of a sliding portion of the camshaft and
the counterpart made of an iron-based material. A hydrogen amount of the
hard carbon film is 10 atomic percent or less.