To provide a combustion device for an on-vehicle internal combustion engine capable of suitably suppressing deterioration of drivability caused by the changeover of a combustion form.

The internal combustion engine 10 is controlled to perform stratified combustion during low speed or low load operation and to perform uniform combustion during medium or higher speed and medium-high load operation. During idling operation conditioned on vehicle speed detected by a vehicle speed sensor 4 being zero, the internal combustion engine 10 is controlled to perform uniform combustion so as to prevent rattling sound from a manual transmission 30. The changeover of a combustion form from uniform combustion to stratified combustion following the start of a vehicle is made on condition that the depressed state of a clutch pedal 45b is detected by a clutch sensor 45 and the nondepressed state of an accelerator pedal 42a is detected by an idle switch 43.