An engine for a vehicle includes a cam chain tensioner actuated by pressure of lubricating oil for stabilizing a movement of a cam chain, a lubricating oil passage through which the lubricating oil is supplied to cam shafts in a cylinder head and a branched lubricating oil passage, branched from the lubricating oil passage, through which the lubricating oil is supplied to the cam chain tensioner. The branched lubricating oil passage is branched from the lubricating oil passage at a portion on an upstream side of an orifice in the lubricating oil passage located upstream of the cylinder head, and in communication with the cam chain tensioner.