An outboard motor that facilitates replacement of an impeller of a water pump includes a water pump arranged to pump coolant and a pump driving mechanism arranged to distribute power from a drive shaft to the water pump. At least a portion of the water pump in which an impeller is housed can be detached and attached from the outside of an upper case. The pump driving mechanism distributes power in a direction generally perpendicular to the axial direction of the drive shaft and transmits the power to the water pump.