The lawn mower (10) comprises an internal combustion engine (100) having a plurality of cylinders, an engine control unit (110) for selectively deactivating at least one of the cylinders, a cutting blade (70) supported by a lawn mower main body via a cutter deck, and connected to the engine in a power transmitting relationship, a clutch (80) provided in a power transmission path between the engine and the cutting blade, a height adjustment mechanism (90) provided on the cutter deck for adjusting the height of the cutting blade, and a central control unit (50) for controlling an operation of the height adjusting mechanism, the clutch and the engine control unit. The central control unit is configured to cause the engine control unit to deactivate at least one of the cylinders when a prescribed operating condition is met, and to raise the cutting blade to a prescribed elevated height before deactivating the at least one of the cylinders.