To provide a bilge water draining device which restrains the lowering of engine power by reducing a resistance loss in a jet water passage in a nozzle, increases thrust force by preventing the generation of turbulent flow, and heightens a spout effect at the same time.

In the bilge water draining device of a water vehicle which drains bilge water by sucking out the bilge water utilizing negative pressure suction work by the jet water of the jet passage by arranging a tapered water injection nozzle 5 at the rear end of a jet water passage in which an impeller is secured, and communicating a bilge water drain pipe 37 with the jet water passage. An opening 34 facing the jet passage is provided in the nozzle 5 and connecting a jet water taking out pipe 31 to the opening 34 without projecting from the inner face of the nozzle 5 and the bilge drain pipe 37 is connected to the jet water taking out pipe 31.