A combustion-powered nail gun drives nails into a workpiece when both a head switch and a trigger switch are turned ON while a safety switch is turned ON. The nail driving operation cannot be performed if the safety switch is not ON even if both the head switch and the trigger switch are ON. The head switch is turned ON when a push lever is urged against the workpiece. Fuel/air mixture in a combustion chamber is ignited when the head switch and the trigger switch are turned ON irrespective of an order in which the head switch and the trigger switch are turned ON, whereby “successive-shot driving” can be performed in which the trigger switch is maintained in its ON position while successively driving a plurality of nails at different locations of the workpiece by repeatedly pushing and releasing the push lever toward and away from the workpiece.