An air-cooling device includes a radiator, a duct, and a fan. The radiator includes a radiator core and a frame connected to an outer peripheral portion of the radiator core. The duct is disposed forward of the radiator. The duct includes an opening disposed forward of the radiator core and an air guide that extends from the frame to an end of the opening. The fan causes air to flow from the opening to the radiator core. The frame is disposed to extend from a position on one side of a straight line to a position on an opposite side of the straight line, the straight line extending rearward from the end of the opening. A connecting portion between the frame and the air guide is located at a distance from the straight line.