PURPOSE: To enable compact equipment of an oil pump and a cooling water pump, and to enhance riding comfortableness by juxtaposing right and left the oil pump and the cooling water pump whose pump shafts are arranged in parallel with the crankshaft, in front of the crankcase, and in the position of the width directional central part.

CONSTITUTION: A cooling water pump 10 and an oil pump 11 are juxtaposed right and left in front of the crankcase 3 of a water-cooled parallel two-cylinder engine so as to be positioned in the central part in its width direction, and the pump shaft 9 of these pumps is made common, and is arranged in parallel with the crankshaft 4. A gear 8 is fixed on the pump shaft 9 in the central position between both pumps 10 and 11, and making an idler of a balancer- driving gear 7, power is input through a gear 5 on the crankshaft 4. The oil pump 11 is constituted as a double pump consisting of an oil discharge pump 11s for sucking lubricating oil from an oil pan and sending it to an oil reserving tank, and an oil supply pump 11f for sucking lubricating oil from the oil reserving tank and supplying it to a lubricating system.