An internal combustion engine includes a cylinder head, a crankshaft, intake and exhaust camshafts, first and second chain covers, a chain, and a fastening bolt. The first chain cover having a cutout includes a first flange positioned at a specific edge portion of the cutout, which is positioned between the crankshaft and the camshafts, and a first boss through which a shaft portion of the fastening bolt is passed. The cylinder head includes a second flange, and a second boss into which the shaft portion is inserted, and which is disposed coaxially with the first boss. The liquid gasket is held between the second flange and the first flange. A groove is provided in at least one of a position between the first flange and the first boss of the first chain cover and a position between the second flange and the second boss of the cylinder head.