ENGINE UNIT INCLUDING INTERNAL COMBUSTION ENGINE AND MISFIRE DETECTION DEVICE, AND VEHICLE

An engine unit includes an internal combustion engine and a misfire detection device. The misfire detection device includes a rough road traveling determination unit that: (a) determines a rough road traveling state based on a distribution state of a crankshaft rotation speed fluctuation physical quantity acquired by a crankshaft rotation speed fluctuation physical quantity acquisition unit, or (b) includes a vehicle traveling state detection unit for detecting a physical quantity in relation to a vehicle traveling state except the crankshaft rotation speed fluctuation physical quantity, and determines a rough road traveling state based on a detection result obtained by the vehicle traveling state detection unit; and suspends a determination of a misfire in the internal combustion engine based on a determination result obtained by the rough road traveling determination unit.