Arrangement of a variable valve mechanism and an oil control valve, said oil control valve comprising a housing and a spool valve that is arranged in the housing and movable in an axial direction of the spool valve, the valve being characterized in that a plurality of ports connected to the variable valve timing mechanism and a lock mechanism are formed in the housing, the oil control valve is adapted to perform: supply/drainage of oil to and from the variable valve timing mechanism to hydraulically operate the variable valve timing mechanism by adjusting a position of the spool valve in the axial direction to selectively open and close the ports with a valve body (18c, 18d) of the spool valve; and supply/drainage of oil to and from the lock mechanism to carry out a prohibiting operation for prohibiting operation of the variable valve timing mechanism and a permitting operation for permitting the operation of the variable valve timing mechanism, the variable valve timing mechanism has a movable member that divides an interior of a case into a phase-advancing hydraulic chamber and a phase-retarding hydraulic chamber, the variable valve timing mechanism is adapted to operate the movable member by supplying oil to one of the phase-advancing and phase-retarding hydraulic chambers (7, 8) and draining oil from the other one of the phase-advancing and phase-retarding hydraulic chambers (7, 8), thereby changing a rotational phase of a camshaft relative to a crankshaft, a passage in which the oil flows is formed in the spool valve, and the valve body (18c, 18d) of the spool valve and the ports of the housing are formed such that: a movement range of the spool valve includes a first area, in which the spool valve opens those of the ports connected to the lock mechanism to perform the prohibiting operation by draining oil from the lock mechanism, and a second area, in which the spool valve performs the supply/drainage of oil to and from the variable valve timing mechanism through the passage; in the second area, the oil is supplied to the phase-advancing hydraulic chamber, and the oil in the phase-retarding hydraulic chamber is drained; the first area is located at a position spaced from the second area in the movement range, the first area and the second area are spaced apart at a predetermined distance; and in the entire predetermined distance, the oil is supplied to the phase-advancing hydraulic chamber, and the oil in the phase-retarding hydraulic chamber is not drained. supply/drainage of oil to and from the variable valve timing mechanism to hydraulically operate the variable valve timing mechanism by adjusting a position of the spool valve in the axial direction to selectively open and close the ports with a valve body (18c, 18d) of the spool valve; and supply/drainage of oil to and from the lock mechanism to carry out a prohibiting operation for prohibiting operation of the variable valve timing mechanism and a permitting operation for permitting the operation of the variable valve timing mechanism, the variable valve timing mechanism has a movable member that divides an interior of a case into a phase-advancing hydraulic chamber and a phase-retarding hydraulic chamber, the variable valve timing mechanism is adapted to operate the movable member by supplying oil to one of the phase-advancing and phase-retarding hydraulic chambers (7, 8) and draining oil from the other one of the phase-advancing and phase-retarding hydraulic chambers (7, 8), thereby changing a rotational phase of a camshaft relative to a crankshaft, a passage in which the oil flows is formed in the spool valve, and the valve body (18c, 18d) of the spool valve and the ports of the housing are formed such that: a movement range of the spool valve includes a first area, in which the spool valve opens those of the ports connected to the lock mechanism to perform the prohibiting operation by draining oil from the lock mechanism, and a second area, in which the spool valve performs the supply/drainage of oil to and from the variable valve timing mechanism through the passage; in the second area, the oil is supplied to the phase-advancing hydraulic chamber, and the oil in the phase-retarding hydraulic chamber is drained; the first area is located at a position spaced from the second area in the movement range, the first area and the second area are spaced apart at a predetermined distance; and in the entire predetermined distance, the oil is supplied to the phase-advancing hydraulic chamber, and the oil in the phase-retarding hydraulic chamber is not drained. a movement range of the spool valve includes a first area, in which the spool valve opens those of the ports connected to the lock mechanism to perform the prohibiting operation by draining oil from the lock mechanism, and a second area, in which the spool valve performs the supply/drainage of oil to and from the variable valve timing mechanism through the passage; in the second area, the oil is supplied to the phase-advancing hydraulic chamber, and the oil in the phase-retarding hydraulic chamber is drained; the first area is located at a position spaced from the second area in the movement range, the first area and the second area are spaced apart at a predetermined distance; and in the entire predetermined distance, the oil is supplied to the phase-advancing hydraulic chamber, and the oil in the phase-retarding hydraulic chamber is not drained.