In an outboard motor, a speed reduction mechanism includes an inner gear connected with an input shaft (i.e., second output shaft), a planetary gear that meshes with the inner gear and that rolls inside the inner gear, and a sun gear that meshes with the planetary gear and that is not rotatable. A shaft portion of a carrier that supports the planetary gear, and a shaft core portion of the sun gear, preferably have a cylindrical or substantially cylindrical shape. The shaft portion of the carrier is inserted and arranged to overlap with the shaft core portion of the sun gear in a direction perpendicular or substantially perpendicular to the shaft. The output shaft (i.e., drive shaft) is inserted and coupled to the shaft portion of the carrier. Accordingly, this provides an outboard motor that makes it possible to prevent the size of a speed change device from increasing in size when a speed reduction mechanism is added.