To improve lubricating performance of an engine in a vertical engine.

An oil pan 13 for storing lubricating oil L is arranged in a lower end part of a crankcase 11, and a crankshaft 14 is rotatably arranged in the crankcase 11 by turning in the vertical direction. A valve system 40 is operated by a driven side sprocket 36 rotatingly driven by the crankshaft 14 via a driving side sprocket 35 and a chain 37, and an oil reserving part 70 is positioned and formed under the valve system 40 on a cylinder head 22. The lubricating oil L is supplied to the oil reserving part 70 from the oil pan 13, and the lubricating oil L supplied to the oil reserving part 70 is splashed up by a splash pump 80 installed in the driven side sprocket 36, and lubricates the valve system 40.