To provide a cooling structure of a clutch device that can improve cooling efficiency of a clutch mechanism by introducing relatively low temperature outside air in a clutch housing.

An outside air introduction opening 23 is arranged on a bottom plate 22 of the clutch housing 2 and a duct 8 extending to a front side of a vehicle is mounted to the outside air introduction opening 23. An outside air introduction hole 83a is formed on a lower surface of the front side of the duct 8 and outside air existing in a space which is hardly affected by radiation heat from an exhaust pipe taken from the outside air introduction hole 83a is introduced into the clutch housing 2 from the outside air introduction opening 23 through an inner passage X of the duct 8. A baffle plate 9 is arranged in an internal space of the clutch housing 2 to guide introduced air to a central part of the clutch housing 2.