A compact snowmobile comprises an engine room having a vertical cross section becoming smaller toward a forward end of the snowmobile, a driver seat having a cross section smaller in area than that of the rear end of the engine room, a radiator disposed at one of paired openings formed respectively at both side portions of the rear end portion of said engine room, and an air-intake passageway formed in a cowl constituting the upper wall of the engine room and intended to feed the air to the radiator.