A cooling device includes a surrounding member, an air inlet, an air outlet, and a flow-path-formation mechanism. The surrounding member is configured to surround an engine. The air inlet is formed in the surrounding member. The air outlet is formed in the surrounding member and is to be coupled to an intake pipe of the engine. The flow-path-formation mechanism is configured to form a flow path that allows outside air to circulate to the air outlet from the air inlet when a temperature of the engine or a temperature inside the surrounding member is greater than or equal to a predetermined temperature.