An engine 10 has a crank shaft 20 which is provided inside a crankcase 12 and an oil pan 18 and penetrating the crankcase 12 and the oil pan 18 in an up-down direction. Inside the oil pan 18, an oil pump 96 and an oil strainer 102 are provided. The oil pump 96 is disposed coaxially with the crank shaft 20 and is driven by the crank shaft 20. The crank shaft 20 has one side and another side respectively supported pivotably by the platy support member 70 and the crankcase 12. The support member 70 is provided in the crankcase 12 in such a fashion that two surfaces of the support member 70 are covered by the crankcase 12 and the oil pan 18 and there can be communication between the crankcase 12 and the oil pan 18.