A bearing cap is bolted to the cylinder head by a cap bolt to fix relative position of the camshaft to the cylinder head. An oil escape bore that connects a cap bolt insert bore formed in the bearing cap through a chain casing to an oil pan is formed in the bearing cap, wherein the oil escape bore is positioned with a distance from a cylinder-head meeting surface of the bearing cap. As a result the oil escape bore is formed without damaging mounting performance of the bearing cap to the cylinder head.