To provide a device in which an oar is bent at a point equivalent to a fulcrum of the oar when a boat is put on an oar, and the boat goes forward when rowing the boat.

An oar is cut off at a point equivalent to a fulcrum of the oar, and there gears 3 and 4 each provided with shaft-hole in the center part are provided and fixed to the cut off oars respectively. In order for the gears 3 and 4 to be freely bent in an engaged state, the gears are nipped between an upper fixing plate 5 and a lower fixing plate 6, and upper and lower plates fastening bolts 11 and 12 are passed through the gear-shaft holes to be tightened. Further, holes 9 and 10 through which oar mounting bolts can be passed, and a supporting pipe 7 are provided in the upper fixing plate 5 and in the lower fixing plate 6.