An electronic control unit (30) included in a control system is configured to execute a change of a combustion mode in an inertia-phase period during a gear shift operation or after the gear shift operation is completed when a request for the change of the combustion mode and a request for a gear shift of the transmission mechanism (10) overlap. The electronic control unit (30) is configured to execute the change of the combustion mode in the inertia-phase period during the gear shift operation when i) and ii) are established, and execute the change of the combustion mode after the gear shift operation is completed when i) and iii) are established: i) the change of the combustion mode is accompanied by an increase in engine power; ii) the power running mode is executed during the gear shift operation; and iii) the regeneration mode is executed during the gear shift operation.
