PURPOSE: To shorten the full length of an internal combustion engine to miniaturize it, and appropriately drive an-oil pump through an exclusive chain, in a V-type internal combustion engine, by dispensing with to elongate the front part of a crankshaft or to projectingly provide an oil pump in front of the engine.

CONSTITUTION: In an engine in which the front end face of a first cylinder head is projectingly provided in front of the front end face of a second cylinder head in the axial direction of a crankshaft, an oil pump driving sprocket 62 is provided between the journal part 12a of the crankshaft and a sprocket 20 for a timing chain. Further, against the oil pump driving sprocket 62, a chain 64 for driving an oil pump 66 and an oil pump sprocket 68 are arranged.