Control unit and control method for variable valve timing mechanism

An electronic control unit (100) for a variable valve timing mechanism (2000, 3000) is disclosed that changes a valve phase of at least one of an intake valve (1100) and an exhaust valve (1110) within a first range from a first phase that is a most retarded phase to a second phase that is a most advanced phase by changing a phase of a camshaft (1120, 1130) with respect to an output shaft (1090) of an internal combustion engine (1000). The electronic control unit (100) comprises a detector (5010) that detects the valve phase; a first phase control unit (110) that executes a control for bringing the valve phase to the first phase, when the internal combustion engine (1000) is stopped; a learning unit (140) that learns the valve phase detected by the detector, when the valve phase is controlled to the first phase; and a second phase control unit (120) that executes a control for changing the valve phase within a second range included in the first range and that does not include the first phase, when the internal combustion engine (1000) is operating.