In an internal combustion engine provided with a combustion chamber defined by an inner circumferential surface of a cylinder, an end surface of a cylinder head facing the cylinder, a crown surface of a piston, an inner surface of an intake valve, and an inner surface of an exhaust valve, for the purpose of improving the anti-knocking performance of the engine, the inner circumferential surface of the cylinder, the end surface of the cylinder head, the crown surface of the piston, the inner surface of the intake valve and the inner surface of the exhaust valve include a mirror surface region formed as a mirror surface having an arithmetic average roughness of 0.3 μm or less, and a rough surface region formed as a rough surface having an arithmetic average roughness of 0.3 μm or more.