A muffler cooling device for a V-type engine which includes an engine cooling fan disposed at an end of a crankshaft. An air guide plate is provided at a part of a duct through which air sucked by the cooling fan flows, and the duct has at least one opening through which the air flows as being guided by the air guide plate. The arrangement is such that the air having flown through the opening is led, through a space surrounded by a V-bank formed by cylinder heads and an intake manifold, to an area in which a muffler and exhaust pipes extending from the cylinder heads to the muffler are arranged.