To improve the lubrication of an input shaft pinion bearing in a reduction reverse gear for a ship.

The reduction reverse gear for the ship has a casing for accommodating a gear mechanism which includes: a forward input gear 32 fixed to a forward input shaft 31; a forward pinion 33 penetrated with the forward input shaft 31; first bearings 331, 332 arranged at two points of the forward pinion 33 in the axial direction; a forward clutch 34 arranged between the forward input gear 32 and the forward pinion 33; a reverse input shaft; a reverse input gear; a reverse pinion; second bearings arranged at two points of the reverse pinion in the axial direction; a retreating clutch; an output gear which is geared with the forward/reverse pinions; and a propeller connected to the output gear. The reduction reverse gear also has a receiving part 225 in which an oil supply passage 314 and at least one of branch passages 3141 to 3144 are formed at the forward/reverse input shaft, and which guides oil from the branch passages to the bearings 331, 332.