A control device for an internal combustion engine that includes: a piston that moves between a top dead center and a bottom dead center; a crankshaft; a camshaft; and a combustion chamber, the control device including: an intake valve (Va) that opens/closes the combustion chamber such that air flows into the combustion chamber; and an exhaust valve (Vb) that opens/closes the combustion chamber such that a combustion gas after combustion flows out of the combustion chamber, the control device comprising: a driving rotating body to which a rotational force is transmitted from the crankshaft; a driven rotating body that is housed within the driving rotating body so as to be rotatable relative to the driving rotating body, and that rotates integrally with the camshaft for opening/closing the exhaust valve (Vb); a lock mechanism that is switchable between a locked state, in which a relative rotation phase of the driving rotating body and the driven rotating body is held in a predetermined first lock phase that is an intermediate phase between a maximum advance phase and a maximum retard phase, and an unlocked state, with which the locked state is released; a phase control valve that is capable of controlling the relative rotation phase of the driving rotating body and the driven rotating body, and controlling the locked state caused by the lock mechanism, by supplying/discharging a fluid to/from an advancing chamber (Ca) or a retarding chamber (Cb), which are defined between the driving rotating body and the driven rotating body; and a control unit that controls the phase control valve, wherein an overlap range of opening/closing timings of the intake valve (Va) and the exhaust valve (Vb) is set such that an open state of the exhaust valve (Vb) is maintained when the relative rotation phase is held in the locked state by the lock mechanism and the piston moves from the top dead center toward the bottom dead center. a driving rotating body to which a rotational force is transmitted from the crankshaft; a driven rotating body that is housed within the driving rotating body so as to be rotatable relative to the driving rotating body, and that rotates integrally with the camshaft for opening/closing the exhaust valve (Vb); a lock mechanism that is switchable between a locked state, in which a relative rotation phase of the driving rotating body and the driven rotating body is held in a predetermined first lock phase that is an intermediate phase between a maximum advance phase and a maximum retard phase, and an unlocked state, with which the locked state is released; a phase control valve that is capable of controlling the relative rotation phase of the driving rotating body and the driven rotating body, and controlling the locked state caused by the lock mechanism, by supplying/discharging a fluid to/from an advancing chamber (Ca) or a retarding chamber (Cb), which are defined between the driving rotating body and the driven rotating body; and a control unit that controls the phase control valve, wherein an overlap range of opening/closing timings of the intake valve (Va) and the exhaust valve (Vb) is set such that an open state of the exhaust valve (Vb) is maintained when the relative rotation phase is held in the locked state by the lock mechanism and the piston moves from the top dead center toward the bottom dead center.