Engine control mechanism

An engine control mechanism includes intake and exhaust valves (11, 10) that opens and closes a combustion chamber (2) of an engine (E) to be driven with gasoline. The engine control mechanism includes: an intake-side VVT (4) including first driving-side and driven-side rotary bodies (41, 42), and capable of setting a valve opening/closing timing of the intake valve such that a relative phase of the first driven-side rotary body is set to an intermediate lock phase at the time of starting of the engine, and the relative phase is set to a more retarded side than the intermediate lock phase after the starting; an exhaust-side VVT (5) including second driving-side and driven-side rotary bodies (51, 52), and setting a valve opening/closing timing of the exhaust valve such that a relative phase of the second driven-side rotary body is set to any phase between the most advanced phase and the most retarded phase; a control unit (6) advance-controlling the ignition timing when an operational state has shifted from an Atkinson cycle state to a transient operational state; and an ignition timing changing mechanism (8) in which the driving is controlled by the control unit.