An oil control valve (60) that controls a valve timing gear mounted on a cylinder head (1) of an internal combustion engine. The oil control valve includes a housing (3) with plural oil lines; a spool type valve (5) that moves in the housing to open and close the oil lines; and a solenoid (31) having a metal case (33) and driving the spool type valve. And this housing (3) is mounted on the cylinder head (1). At least a part of the metal case (33) passes through a through hole (183) through a cylinder head cover (18) covering the cylinder head (1) and is disposed outside the cylinder head cover (18). As a result, all parts of the oil control valve (60) are disposed inside the head cover (18), and even in case of oil leakage, the oil does not leak out of the engine.